Added ANTLR. Fix Issue #20960

[DavidGrath]

PR checklist

• Read the contribution guidelines.
• Pull Request title clearly describes the work in the pull request and Pull Request description provides details about how to validate the work. Missing information here may result in delayed response from the community.
• Run the following to build the project and update samples:

  ./mvnw clean package || exit
  ./bin/generate-samples.sh ./bin/configs/*.yaml || exit
  ./bin/utils/export_docs_generators.sh || exit
  

  (For Windows users, please run the script in Git BASH)
  Commit all changed files.
  This is important, as CI jobs will verify all generator outputs of your HEAD commit as it would merge with master.
  These must match the expectations made by your contribution.
  You may regenerate an individual generator by passing the relevant config(s) as an argument to the script, for example ./bin/generate-samples.sh bin/configs/java*.
  IMPORTANT: Do NOT purge/delete any folders/files (e.g. tests) when regenerating the samples as manually written tests may be removed.
• File the PR against the correct branch: master (upcoming 7.x.0 minor release - breaking changes with fallbacks), 8.0.x (breaking changes without fallbacks)
• If your PR is targeting a particular programming language, @mention the technical committee members, so they are more likely to review the pull request.

I'm taking inspiration from #3715 by @sullis and #11738 by @borsch to try and add parsing utilities for Kotlin and possibly other languages. For now, though, it's just to fix this issue.
Kotlin Grammar gotten from https://github.com/antlr/grammars-v4

@4brunu, please help review

[wing328]

thanks for the PR

please review the build failure when you've time

[wing328]

what about using spaces instead of tabs?

shall we fix the javadoc issue instead of excluding these from the tests?

[DavidGrath]

Good Day,
I'm not sure what you mean exactly, so please can you help me to clarify?
My main issue comes from the fact that it seems the JavaDoc plugin doesn't recognize the ANTLR packages because the dependency is in test scope.
Are you saying that instead of excluding the generated files from scanning, I should find a way to let them be scanned without also causing classpath issues?
Also, sorry about the inconsistent whitespace, I'll fix it

[wing328]

My main issue comes from the fact that it seems the JavaDoc plugin doesn't recognize the ANTLR packages because the dependency is in test scope.

👌

please ignore my comment on that

[DavidGrath]

Okay. Tabs removed from the pom files