Quick fix to declare overridden method on base class

From https://github.com/microsoft/vscode/issues/129130#issuecomment-885409056

Suggestion

Add a new quick fix on a subclass that tried to override a non-existent method to add that method to the base class.

For example, starting with:

class Base {

}

class Sub extends Base {
	override foo() {}
}

The quick fix would generate:

class Base {
	foo() {
		throw new Error("Not implemented");
	}
}

class Sub extends Base {
	override foo() {}
}

🔍 Search Terms

• Override
• quick fix
• code action

Start by locating the TypeScript language-service quick-fix or code-action handling for an override of a non-existent method. Trace how the diagnostic is produced, then inspect the existing quick-fix tests before adding coverage for the Base and Sub example. Done means the quick fix generates the base method with the shown not-implemented body.