[Docs Bug 🐞 report]: multiple broken and empty links across /docs

### Describe the bug you found in AsyncAPI Docs.

I came across several broken, empty, or outdated links while going through the Modelina docs. Listing them below with the current behavior and the correct links where applicable.
## 1. Champions page

**Page:** [https://modelina.org/docs/champions](https://modelina.org/docs/champions)

* Empty links:

* `Versioning and maintenance`
* `Reviewing a PR`

---

## 2. Constraints page

**Page:** [https://modelina.org/docs/constraints](https://modelina.org/docs/constraints)

* Link text: `read more about the process here`

* Current: [https://github.com/asyncapi/modelina/blob/master/internal-model.md](https://github.com/asyncapi/modelina/blob/master/internal-model.md)
* Should be: [https://github.com/asyncapi/modelina/blob/master/docs/internal-model.md](https://github.com/asyncapi/modelina/blob/master/docs/internal-model.md)

---

## 3. XSD input docs

**Page:** [https://modelina.org/docs/inputs/xsd](https://modelina.org/docs/inputs/xsd)

* Link text: `Usage documentation`

* Current (404): [https://github.com/asyncapi/modelina/blob/master/usage.md](https://github.com/asyncapi/modelina/blob/master/usage.md)
* Should be: [https://github.com/asyncapi/modelina/blob/master/docs/usage.md](https://github.com/asyncapi/modelina/blob/master/docs/usage.md)

---

## 4. Internal model page

**Page:** [https://modelina.org/docs/internal-model](https://modelina.org/docs/internal-model)

* Empty link:

* `see the splitting of meta models`
* Broken link:

* `the constraint behavior here`

* Current: https://modelina.org/docs/constraints/README
* Should be: [https://github.com/asyncapi/modelina/blob/master/docs/constraints/README.md](https://github.com/asyncapi/modelina/blob/master/docs/constraints/README.md)

---

## 5. Java language docs

**Page:** [https://modelina.org/docs/languages/java#jackson-annotation](https://modelina.org/docs/languages/java)

* Broken link:
* `You can find the integration example here`

* Current (404): [https://github.com/asyncapi/modelina/blob/master/integration.md#integrate-with-maven](https://github.com/asyncapi/modelina/blob/master/integration.md#integrate-with-maven)
* Should be: [https://github.com/asyncapi/modelina/blob/master/docs/integration.md#integrate-modelina-into-maven](https://github.com/asyncapi/modelina/blob/master/docs/integration.md#integrate-modelina-into-maven)

---

## 6. Rust language docs

**Page:** [https://modelina.org/docs/languages/rust](https://modelina.org/docs/languages/rust)

* Empty links:

* Implement From (serde_json)
* Implement Into (serde_json)
* Implement From (tokio_serde)
* Implement Into (tokio_serde)

---

## 7. Constraints section issues

### a. General broken links

* Link text: `Read here to get a more general idea on the overall process`

* Current (404): [https://github.com/asyncapi/modelina/blob/master/input-processing.md](https://github.com/asyncapi/modelina/blob/master/input-processing.md)
* Should be: [https://github.com/asyncapi/modelina/blob/master/docs/input-processing.md](https://github.com/asyncapi/modelina/blob/master/docs/input-processing.md)

* Link text: `see the full list here`

* 404 for multiple languages (not present in Kotlin, PHP, Scala)

### b. Constants.ts links missing `master`

These currently miss `/master/` in the path:

* C#:
[https://github.com/asyncapi/modelina/blob/src/generators/csharp/Constants.ts](https://github.com/asyncapi/modelina/blob/src/generators/csharp/Constants.ts)
→ [https://github.com/asyncapi/modelina/blob/master/src/generators/csharp/Constants.ts](https://github.com/asyncapi/modelina/blob/master/src/generators/csharp/Constants.ts)

* C++:
[https://github.com/asyncapi/modelina/blob/src/generators/cplusplus/Constants.ts](https://github.com/asyncapi/modelina/blob/src/generators/cplusplus/Constants.ts)
→ [https://github.com/asyncapi/modelina/blob/master/src/generators/cplusplus/Constants.ts](https://github.com/asyncapi/modelina/blob/master/src/generators/cplusplus/Constants.ts)

* Dart:
[https://github.com/asyncapi/modelina/blob/src/generators/dart/Constants.ts](https://github.com/asyncapi/modelina/blob/src/generators/dart/Constants.ts)
→ [https://github.com/asyncapi/modelina/blob/master/src/generators/dart/Constants.ts](https://github.com/asyncapi/modelina/blob/master/src/generators/dart/Constants.ts)

* Go:
[https://github.com/asyncapi/modelina/blob/src/generators/go/Constants.ts](https://github.com/asyncapi/modelina/blob/src/generators/go/Constants.ts)
→ [https://github.com/asyncapi/modelina/blob/master/src/generators/go/Constants.ts](https://github.com/asyncapi/modelina/blob/master/src/generators/go/Constants.ts)

* Java:
[https://github.com/asyncapi/modelina/blob/src/generators/java/Constants.ts](https://github.com/asyncapi/modelina/blob/src/generators/java/Constants.ts)
→ [https://github.com/asyncapi/modelina/blob/master/src/generators/java/Constants.ts](https://github.com/asyncapi/modelina/blob/master/src/generators/java/Constants.ts)

* JavaScript:
[https://github.com/asyncapi/modelina/blob/src/generators/javascript/Constants.ts](https://github.com/asyncapi/modelina/blob/src/generators/javascript/Constants.ts)
→ [https://github.com/asyncapi/modelina/blob/master/src/generators/javascript/Constants.ts](https://github.com/asyncapi/modelina/blob/master/src/generators/javascript/Constants.ts)

* Python:
[https://github.com/asyncapi/modelina/blob/src/generators/python/Constants.ts](https://github.com/asyncapi/modelina/blob/src/generators/python/Constants.ts)
→ [https://github.com/asyncapi/modelina/blob/master/src/generators/python/Constants.ts](https://github.com/asyncapi/modelina/blob/master/src/generators/python/Constants.ts)

* Rust:
[https://github.com/asyncapi/modelina/blob/src/generators/rust/Constants.ts](https://github.com/asyncapi/modelina/blob/src/generators/rust/Constants.ts)
→ [https://github.com/asyncapi/modelina/blob/master/src/generators/rust/Constants.ts](https://github.com/asyncapi/modelina/blob/master/src/generators/rust/Constants.ts)

* TypeScript:
[https://github.com/asyncapi/modelina/blob/src/generators/typescript/Constants.ts](https://github.com/asyncapi/modelina/blob/src/generators/typescript/Constants.ts)
→ [https://github.com/asyncapi/modelina/blob/master/src/generators/typescript/Constants.ts](https://github.com/asyncapi/modelina/blob/master/src/generators/typescript/Constants.ts)

---

## 8. Migrations pages

**Page:** [https://modelina.org/docs/migrations](https://modelina.org/docs/migrations)

Incorrect links:

* From v0 to v1
[https://modelina.org/docs/version-0-to-1](https://modelina.org/docs/version-0-to-1)
→ [https://modelina.org/docs/migrations/version-0-to-1](https://modelina.org/docs/migrations/version-0-to-1)

* From v1 to v2
[https://modelina.org/docs/version-1-to-2](https://modelina.org/docs/version-1-to-2)
→ [https://modelina.org/docs/migrations/version-1-to-2](https://modelina.org/docs/migrations/version-1-to-2)

* From v2 to v3
[https://modelina.org/docs/version-2-to-3](https://modelina.org/docs/version-2-to-3)
→ [https://modelina.org/docs/migrations/version-2-to-3](https://modelina.org/docs/migrations/version-2-to-3)

* From v3 to v4
[https://modelina.org/docs/version-3-to-4](https://modelina.org/docs/version-3-to-4)
→ [https://modelina.org/docs/migrations/version-3-to-4](https://modelina.org/docs/migrations/version-3-to-4)

### Constraints links on v0 → v1 page

GitHub links for constraints should be:

* C++: [https://github.com/asyncapi/modelina/blob/master/docs/constraints/Cplusplus.md](https://github.com/asyncapi/modelina/blob/master/docs/constraints/Cplusplus.md)
* C#: [https://github.com/asyncapi/modelina/blob/master/docs/constraints/CSharp.md](https://github.com/asyncapi/modelina/blob/master/docs/constraints/CSharp.md)
* Dart: [https://github.com/asyncapi/modelina/blob/master/docs/constraints/Dart.md](https://github.com/asyncapi/modelina/blob/master/docs/constraints/Dart.md)
* Go: [https://github.com/asyncapi/modelina/blob/master/docs/constraints/Go.md](https://github.com/asyncapi/modelina/blob/master/docs/constraints/Go.md)
* Java: [https://github.com/asyncapi/modelina/blob/master/docs/constraints/Java.md](https://github.com/asyncapi/modelina/blob/master/docs/constraints/Java.md)
* JavaScript: [https://github.com/asyncapi/modelina/blob/master/docs/constraints/JavaScript.md](https://github.com/asyncapi/modelina/blob/master/docs/constraints/JavaScript.md)
* Kotlin: [https://github.com/asyncapi/modelina/blob/master/docs/constraints/Kotlin.md](https://github.com/asyncapi/modelina/blob/master/docs/constraints/Kotlin.md)
* PHP: [https://github.com/asyncapi/modelina/blob/master/docs/constraints/PHP.md](https://github.com/asyncapi/modelina/blob/master/docs/constraints/PHP.md)
* Python: [https://github.com/asyncapi/modelina/blob/master/docs/constraints/Python.md](https://github.com/asyncapi/modelina/blob/master/docs/constraints/Python.md)
* Rust: [https://github.com/asyncapi/modelina/blob/master/docs/constraints/Rust.md](https://github.com/asyncapi/modelina/blob/master/docs/constraints/Rust.md)
* Scala: [https://github.com/asyncapi/modelina/blob/master/docs/constraints/Scala.md](https://github.com/asyncapi/modelina/blob/master/docs/constraints/Scala.md)
* TypeScript: [https://github.com/asyncapi/modelina/blob/master/docs/constraints/TypeScript.md](https://github.com/asyncapi/modelina/blob/master/docs/constraints/TypeScript.md)

### Internal model anchor links

* `ConstrainedMetaModel`, `ConstrainedObjectPropertyModel`, `ConstrainedEnumValueModel`

* Current: [https://github.com/asyncapi/modelina/blob/master/internal-model.md#the-constrained-meta-model](https://github.com/asyncapi/modelina/blob/master/internal-model.md#the-constrained-meta-model)
* Should be: [https://github.com/asyncapi/modelina/blob/master/docs/internal-model.md#the-constrained-meta-model](https://github.com/asyncapi/modelina/blob/master/docs/internal-model.md#the-constrained-meta-model)

### v1 → v2 page

* Discriminator link points to outdated AsyncAPI spec:
[https://v2.asyncapi.com/docs/reference/specification/v2.6.0#schemaComposition](https://v2.asyncapi.com/docs/reference/specification/v2.6.0#schemaComposition)
→ [https://www.asyncapi.com/blog/release-notes-3.0.0](https://www.asyncapi.com/blog/release-notes-3.0.0)

* “meta model” link:
[https://github.com/asyncapi/modelina/blob/master/internal-model.md](https://github.com/asyncapi/modelina/blob/master/internal-model.md)
→ [https://github.com/asyncapi/modelina/blob/master/docs/internal-model.md#the-meta-model](https://github.com/asyncapi/modelina/blob/master/docs/internal-model.md#the-meta-model)

---

## 9. Other tools page

**Page:** [https://modelina.org/docs/other-tools](https://modelina.org/docs/other-tools)

* Link text: `controlled by the constrainer`

* Current (404): [https://modelina.org/docs/constraints/README](https://modelina.org/docs/constraints/README)
* Should be: [https://github.com/asyncapi/modelina/blob/master/docs/constraints/README.md](https://github.com/asyncapi/modelina/blob/master/docs/constraints/README.md)

### Attach any resources that can help us understand the issue.

### Code of Conduct

- [x] I agree to follow this project's Code of Conduct

### Are you willing to work on this issue ?

Yes I am willing to submit a PR!

Locate the documentation sources for the champions, constraints, inputs, languages, migrations, internal-model, and other-tools pages, along with the listed src/generators/*/Constants.ts files. Check each reported link against its stated replacement, then verify that the affected documentation links resolve and the empty links are populated.

Written by the indexing model from the issue text.