Added a class to the nelmio_api_doc.generator_locator service definition

[derrabus]

I've upgraded an application that uses this bundle to Symfony 5.3, which resulted in the following error:

The definition for "nelmio_api_doc.generator_locator" has no class. If you intend to inject this service dynamically at runtime, please mark it as synthetic=true. If this is an abstract definition solely used by child definitions, please add abstract=true, otherwise specify a class to get rid of this error.

Symfony's documentation on service locators uses a dedicated class, but NelmioApiDocExtension doesn't.

I've fixed the error by adding the documented class to the service definition.

Fixes #1807

[michaljusiega]

See #1807 ;)

[derrabus]

Oh, I did not see that issue. Thanks, I've linked it in the description.

[GuilhemN]

Great! Thank you @derrabus and @michaljusiega :)

[derrabus]

Thank you very much for merging, @GuilhemN! May I ask you to merge 3.x into master? This would unblock further tests with Symfony 5.3 for me because my app already uses version 4 of this bundle.

[GuilhemN]

Sure, it's done :)

[derrabus]

Thank you! ❤️

[Yozhef]

@GuilhemN can you please release this fix in 4.1 version

[derrabus]

@Yozhef See #1825 for this discussion.

[GuilhemN]

done @Yozhef, see https://github.com/nelmio/NelmioApiDocBundle/releases/tag/v4.3.0