Add Vespa Schema Definition language

[thomasht86]

Description

Add Vespa Schema Definition as a new language. Vespa .sd files define document schemas, ranking profiles, and indexing pipelines for the Vespa search engine. The language has programming characteristics — ranking expressions, tensor operations, conditional logic, and ONNX model integration.

The grammar lives in the vespa-engine/vespa monorepo at integration/tmgrammar/grammar/vespa-schema.tmLanguage.json. Since the grammar directory is named grammar/ (singular) rather than the conventional grammars/, "grammar" was added to GrammarsInNonStdPath in tools/grammars/compiler/data.go. No other submodules use a grammar/ directory with .json files, so there are no false positives.

The .sd extension is not currently claimed by any other language in linguist. Heuristics are included proactively to match Vespa keywords (schema, document, field, rank-profile).

Checklist:

• I am adding a new language.
  • The extension of the new language is used in hundreds of repositories on GitHub.com.
    • Search results for .sd extension:
      • https://github.com/search?type=code&q=NOT+is%3Afork+path%3A*.sd+schema
  • I have included a real-world usage sample for all extensions added in this PR:
    • Sample source(s):
      • music.sd: https://github.com/vespa-engine/vespa/blob/master/config-model/src/test/derived/music/music.sd
      • msmarco.sd: https://github.com/vespa-engine/vespa/blob/master/client/go/internal/cli/cmd/testdata/applications/withSource/src/main/application/schemas/msmarco.sd
      • ranking.sd: https://github.com/vespa-engine/vespa/blob/master/config-model/src/test/derived/globalphase_token_functions/test.sd
    • Sample license(s): Apache-2.0
  • I have included a syntax highlighting grammar: https://github.com/vespa-engine/vespa (integration/tmgrammar/grammar/vespa-schema.tmLanguage.json)
  • I have added a color
    • Hex value: #61D790
    • Rationale: Derived from the green in the Vespa logo/branding
  • I have updated the heuristics to distinguish my language from others using the same extension.

[lildude]

See inline comments.

[thomasht86]

Thanks a lot for the quick feedback @lildude!
I see you added "pending popularity" label, but afaict there are a lot more than the requirements?
Vespa Schemas are also most commonly in the "1 per application" - category, althought it is possible to have multiple.
Any chance you could reconsider? 🙏

[thomasht86]

ping @lildude - any pointer on what needs to be done to get this through? ☺️

[lildude]

Popularity is reassessed when preparing for a new release, which happens approximately every 3 months.