Support the `@private` JSDoc directive to exclude private APIs from emitted type declarations

Nobody has claimed this yet.

### 🔍 Search Terms

"private jsdoc"

### ✅ Viability Checklist

- [x] This wouldn't be a breaking change in existing TypeScript/JavaScript code
- [x] This wouldn't change the runtime behavior of existing JavaScript code
- [x] This could be implemented without emitting different JS based on the types of the expressions
- [x] This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, new syntax sugar for JS, etc.)
- [x] This isn't a request to add a new utility type: https://github.com/microsoft/TypeScript/wiki/No-New-Utility-Types
- [x] This feature would agree with the rest of our Design Goals: https://github.com/Microsoft/TypeScript/wiki/TypeScript-Design-Goals

### ⭐ Suggestion

Could properties, functions, and classes annotated with the [`@private`](https://jsdoc.app/tags-private) JSDoc directive be omitted from the emitted declarations?

tsc should throw an error if a symbol is marked as `@private`, but is actually imported/exported from another declaration file or used in the signature of another symbol like a function parameter or return type. (And therefore isn't actually an internal API.)

I'm wary this may break some projects if implemented without an opt-in, so it may require an option to enable this behavior, to preserve backward compatibility.

#### Source

> The `@private` tag marks a symbol as private, or not meant for general use. Private members are not shown in the generated output…
> …
> The `@private` tag is equivalent to `@access private`.
>
> — https://jsdoc.app/tags-private

Based on this, it may be worth also doing it for [`@access private`](https://jsdoc.app/tags-access) as well.

> Private members are not shown in the generated output…
>
> — https://jsdoc.app/tags-access

### 📃 Motivating Example

I maintain a [svgo](https://github.com/svg/svgo), a library that is written in JavaScript and typed with JSDoc directives, and uses tsc to emit declaration files.

As a library normally has an intended public API, afaik there's no need to distribute type declarations for the internal API.

### 💻 Use Cases

This is just to reduce the amount of type declarations served to developers if they aren't needed, reducing the size of the package on npm a little.

No workaround is currently needed, assuming the project is a module that uses `exports` rather than `main`, as we can limit the public API ourselves. The extra types do not cause any harm, it just makes the final package a little bigger.

For projects that use `main` instead of `exports` in their `package.json`, this may leak more private APIs that end-users may accidently consume and believe to be part of the public interface.

Start by reproducing the motivating JavaScript/JSDoc case from svgo with TypeScript declaration emission. Define how @private and possibly @access private affect emitted declarations, including errors for exported or signature-referenced symbols, and determine whether an opt-in option is needed for compatibility.

Written by the indexing model from the issue text.