Add override keyword in codebase (#120755)

For #120675

This uses a script to add the override keyword to places that need it in the codebase

Note that we can't enable the --noImplicitOverride setting yet since there are still around 200 errors that require further attention

src/vs/workbench/api/browser/mainThreadUriOpeners.ts

@@ -128,7 +128,7 @@ export class MainThreadUriOpeners extends Disposable implements MainThreadUriOpe
 		this._contributedExternalUriOpenersStore.delete(id);
 	}
 
-	dispose(): void {
+	override dispose(): void {
 		super.dispose();
 		this._registeredOpeners.clear();
 	}