fix: memory leak in mainThreadLanguages

[SimonSiefke]

Fixes a memory leak in mainThreadLanguages.

Details

The code currently uses

this._status.get(handle)?.dispose();

However that code only disposes the entry, but doesn't remove it from this._status.

Change

Thankfully, DisposableMap provides deleteAndDispose which both disposes the entry and removes it from the map:

this._status.deleteAndDispose(handle);

Also there are some minor code changes trying to simplify the code a bit.

Before

When toggling semantic tokens 37 times, the number of LanguageFeatureRegistry.register functions seems to grow by 1 each time:

After

No more leak detected

[connor4312]

thanks!