Re-add ArkTS Support

[Groupguanfang]

Add ArkTS language support with .ets extension

Description

This PR adds support for ArkTS as a new programming language in Linguist. ArkTS is a superset of TypeScript used for HarmonyOS development, featuring additional language constructs like struct declarations, HarmonyOS-specific decorators, and APIs.

The changes include:

• Added ArkTS as a new language in languages.yml with .ets file extension
• Added official ArkTS syntax highlighting grammar from the ohosvscode/arkTS repository
• Added real-world sample files demonstrating typical ArkTS usage patterns
• Configured proper TextMate scope (source.ets) and language ID

Checklist:

• I am adding a new extension to a language.

  • The new extension is used in hundreds of repositories on GitHub.com
    • Search results for each extension:
      • https://github.com/search?type=code&q=NOT+is%3Afork+path%3A*.FOOBAR+KEYWORDS
  • 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 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?type=code&q=NOT+is%3Afork+path%3A*.ets+ArkTS
      • https://github.com/search?type=code&q=NOT+is%3Afork+path%3A*.ets+HarmonyOS
  • I have included a real-world usage sample for all extensions added in this PR:
    • Sample source(s):
      • Termony: https://github.com/TermonyHQ/Termony (Termux for HarmonyOS Computer. Working in Progress.)
      • ClashBox: https://github.com/xiaobaigroup/ClashBox/tree/master (Open Source HarmonyOS NEXT Proxy App, base on clash mihomo core)
      • HarmonyOS-Haps: https://github.com/Zitann/HarmonyOS-Haps (A collection of open source projects for HarmonyOS Next Hap)
    • Sample license(s):
      • MIT (samples created specifically for this PR)
  • I have included a syntax highlighting grammar: ohosvscode/arkTS
    • Grammar file: packages/vscode/syntaxes/ets.tmLanguage.json
    • TextMate scope: source.ets
  • I have added a color
    • Hex value: #0080ff
    • Rationale: Used the same color as TypeScript since ArkTS is a superset of TypeScript, maintaining visual consistency while indicating the relationship between the languages
  • I have updated the heuristics to distinguish my language from others using the same extension.
    • ArkTS uses .ets extension exclusively and has unique language constructs like struct declarations and HarmonyOS-specific decorators

• 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

  • Added vendor/grammars/ArkTS submodule pointing to ohosvscode/arkTS
  • Updated grammars.yml to map the grammar to source.ets scope
  • Updated vendor/README.md to include the new grammar

• 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]

It still looks like you've not used the script/add-grammar script to add the grammar. Please use that script and don't do it manually. You can use a Codespace (see the CONTRIBUTING.md file) if you're struggling in your own environment.