Fixes #285890 (related: microsoft/monaco-editor#4702 )

Description

This PR fixes unhandled CancellationError exceptions that occur when the WordHighlighter is disposed while a delayed operation is pending.

The Delayer.trigger() method returns a Promise that rejects with CancellationError when cancelled (e.g., during disposal). Without proper error handling, this causes unhandled promise rejection warnings.

Changes

Added .catch(onUnexpectedError) to all three runDelayer.trigger() calls in wordHighlighter.ts.

The onUnexpectedError function from vs/base/common/errors automatically filters out CancellationError, so only genuine unexpected errors are reported.

This follows the same pattern used in other editor contributions:

• parameterHintsModel.ts
• findWidget.ts
• stickyScrollModelProvider.ts

How to test

1. Clone https://github.com/y-scope/yscope-log-viewer.git
2. Run npm ci then npm run dev
3. Open the browser console - without this fix, you'll see:

   Uncaught (in promise) Canceled: Canceled
       CancellationError errors.js:91
       cancel async.js:251
       dispose async.js:260
       dispose lifecycle.js:24
       clear lifecycle.js:114
       dispose lifecycle.js:98
       dispose wordHighlighter.js:652
       dispose wordHighlighter.js:709
       dispose lifecycle.js:24
   

4. Replace the monaco-editor assets in the project with the built assets from this PR
5. Restart the dev server (npm run dev)
6. Verify the CancellationError warning no longer appears in the browser console