Improve support for ABAP CDS

[BeckerWdf]

Support for ABAP CDS was introduces with PR #4614.

".acds" is just another alternative file extension to ".asddls".
This is officially documented by SAP in
https://github.com/SAP/abap-file-formats

See:

• https://github.com/SAP/abap-file-formats/blob/main/docs/specification.md
• https://github.com/SAP/abap-file-formats/tree/main/file-formats/ddls/examples
• https://github.com/SAP/abap-file-formats/tree/main/file-formats/ddlx/examples

Description

Checklist:

• I am associating a language with a new file extension.

  • The new extension is used in hundreds of repositories on github.com
    • Search results for each extension:
      • https://github.com/search?utf8=%E2%9C%93&type=Code&ref=searchresults&q=extension%3AFOOBAR+KEYWORDS+NOT+nothack
  • I have included a real-world usage sample for all extensions added in this PR:
    • Sample source(s):
      • [URL to each sample source, if applicable]
    • Sample license(s):
  • I have included a change to the heuristics to distinguish my language from others using the same extension.

• I am adding a new language.

  • The extension of the new language is used in hundreds of repositories on github.com.
    • Search results for each extension:
      • https://github.com/search?utf8=%E2%9C%93&type=Code&ref=searchresults&q=extension%3AFOOBAR+KEYWORDS+NOT+nothack
  • I have included a real-world usage sample for all extensions added in this PR:
    • Sample source(s):
      • [URL to each sample source, if applicable]
    • Sample license(s):
  • I have included a syntax highlighting grammar: [URL to grammar repo]
  • I have updated the heuristics to distinguish my language from others using the same extension.

• I am fixing a misclassified language

  • I have included a new sample for the misclassified language:
    • Sample source(s):
      • [URL to each sample source, if applicable]
    • Sample license(s):
  • I have included a change to the heuristics to distinguish my language from others using the same extension.

• I am changing the source of a syntax highlighting grammar

  • Old: [URL to grammar repo]
  • New: [URL to grammar repo]

• I am updating a grammar submodule

• I am adding new or changing current functionality

  • I have added or updated the tests for the new or changed functionality.

• I am changing the color associated with a language

  • I have obtained agreement from the wider language community on this color change.
    • [URL to public discussion]
    • [Optional: URL to official branding guidelines for the language]

[lildude]

You appear to have missed a few details in the CONTRIBUTING.md file regarding adding a sample, and more importantly about usage requirements.

There are only three files indexed on GitHub right now, two of which you referenced 😁. This is a long long long way from our standard usage requirements and even our temporarily relaxed requirements detailed in #5756.

I'm closing this PR as the usage is a long way from meeting inclusion requirements and I doubt it'll go from 3 to 2000 or 200 unique repos any time soon. Please feel free to submit a new PR when usage levels are higher. In the meantime you can use an override in your repos to set the language.

[BeckerWdf]

In the meantime you can use an override in your repos to set the language.

Can you pls. explain what exactly using an "override" means?

[lildude]

Sure. We've got a doc for that: https://github.com/github/linguist/blob/master/docs/overrides.md