Config in application.yml has no effect with ksp

### Expected Behavior

[The documentation](https://micronaut-projects.github.io/micronaut-openapi/6.20.0/guide/index.html#applicationConfiguration) refers to `application.yml` as being a possible configuration source for Micronaut OpenAPI processing.

Unfortunately this has no effect when using KSP. A warning should be added to the documentation about it.

There should also be an example of the most elegant configuration when using KSP e.g.

```
ksp {
arg("micronaut.openapi.project.dir", projectDir.toString())
arg("micronaut.openapi.property.naming.strategy", "SNAKE_CASE")
}
```

### Actual Behaviour

_No response_

### Steps To Reproduce

_No response_

### Environment Information

_No response_

### Example Application

_No response_

### Version

5.0.0

Open the linked applicationConfiguration section in the Micronaut OpenAPI guide and review how configuration sources are documented. Add a warning that application.yml has no effect with KSP, include the shown ksp arg example, and verify the resulting documentation clearly identifies the KSP configuration path.

Written by the indexing model from the issue text.