typescript-basics: fix highlighting for triple-slash reference directives with preserve="true"

Does this issue occur when all extensions are disabled?: Yes

• versions

Version: 1.108.2
Commit: c9d77990917f3102ada88be140d28b038d1dd7c7
Date: 2026-01-21T13:52:09.270Z
Electron: 39.2.7
ElectronBuildId: 12953945
Chromium: 142.0.7444.235
Node.js: 22.21.1
V8: 14.2.231.21-electron.0
OS: Windows_NT x64 10.0.19045

Problem

TypeScript supports preserve="true" on triple-slash reference directives, e.g.

/// <reference path="../communication-api.d.ts" preserve="true" />

However, VS Code's bundled TypeScript TextMate grammar fails to recognize the directive when preserve="true" is present, causing the line to be tokenized as a regular line comment instead of a reference directive.

Expected behavior

/// <reference ... /> should be tokenized/highlighted as a reference directive regardless of the presence of preserve="true".

Actual behavior

When preserve="true" is present, the entire line is highlighted as a regular line comment (directive tokenization does not apply).

Repro

1. Open a .ts file in VS Code
2. Add the following baseline line (this is highlighted as a reference directive):

/// <reference path="../communication-api.d.ts" />

3. Now add preserve="true" (this becomes a regular comment highlight):

/// <reference path="../communication-api.d.ts" preserve="true" />

4. Observe that only the preserve="true" form loses directive highlighting.

Evidence (Inspect Editor Tokens and Scopes)

Without preserve="true"

• textmate scopes:
  • punctuation.definition.comment.ts
  • comment.line.triple-slash.directive.ts
  • source.ts
  • comment.line

With preserve="true"

• textmate scopes:
  • comment.line.double-slash.ts
  • source.ts
  • comment.line

Potential fix

Update extensions/typescript-basics/syntaxes/TypeScript.tmLanguage.json under repository/directives to allow the optional preserve="true" attribute in /// <reference ... /> directives.

This makes directives with preserve="true" highlight consistently with the existing path/types/lib reference directives.

Notes

• The change is limited to the directive-matching pattern and does not affect general comment tokenization.
• Handles common spacing variants (e.g. preserve="true"/> and preserve="true" />).

Tests

• Manual verification in VS Code:

  • /// <reference path="..." /> (unchanged)
  • /// <reference path="..." preserve="true" /> (now highlighted as directive)
  • Same for types and lib forms

• (Optional) Add/adjust a colorize fixture under extensions/typescript-basics/test/colorize-fixtures/ to cover the preserve="true" case.

Start in extensions/typescript-basics/syntaxes/TypeScript.tmLanguage.json, especially the repository/directives pattern described in the issue. Review the existing colorize fixtures under extensions/typescript-basics/test/colorize-fixtures/ and verify that path, types, and lib directives still highlight correctly with and without preserve="true".