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/base/browser/dom.ts

@@ -1589,7 +1589,7 @@ export class ModifierKeyEmitter extends Emitter<IModifierKeyStatus> {
 		return ModifierKeyEmitter.instance;
 	}
 
-	dispose() {
+	override dispose() {
 		super.dispose();
 		this._subscriptions.dispose();
 	}