Add a prompt for Extract local variable

[lsaudon]

Is your feature request related to a problem? Please describe.
I'd like to see a prompt for Extract local variable as well as for Extract method.

Describe the solution you'd like
Add a prompt after select Extract local variable.

Describe alternatives you've considered
After extract, trigger Rename symbol vscode.

[DanTup]

The way this was implemented (prompting for a name like Extract Method) has resulted in losing the server-generated name and I think that's made this much worse. I'm going to revert this for now, and try to find a better way to rename (such as triggering the rename automatically if it's possible).

Issue tracking the revert is #4786, and I'll re-open this to track a new solution.

[lsaudon]

Also, why when I do this:

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(),
      ),
    );
  }

I can't extract AppBar() with name appBar ? I have this message The name 'appBar' is already used in the scope..
Likewise, I can rename with appBar after extract.

[DanTup]

@lsaudon I'm not sure - could you file a new issue about that with exact instructions of what you're selecting and invoking? Thanks!