Fix updating items in the quick-pick menu

[vinokurig]

Signed-off-by: Igor Vinokur ivinokur@redhat.com

What it does

Rework the quick-input API to use the $createOrUpdate method in the step of initialising the quick-pick instead of using a separate method $showCustomQuickPick

How to test

1. Clone and compile the test plugin: https://github.com/microsoft/vscode-extension-samples/tree/main/quickinput-sample
2. Start hosted plugin
3. Execute the Quick Input Samples from the command palette.
4. Try all the submenus, especially quickOpen as it is broken in master.

Review checklist

• As an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• As a reviewer, I agree to behave in accordance with the review guidelines

[azatsarynnyy]

I'm not sure if it's the right behavior, but when I'm choosing quickOpen I see

[vinokurig]

@azatsarynnyy
This command works in the same way in vscode:

The aim is to see some output, in the current master this command shows nothing.

[azatsarynnyy]

I see. Except quickOpen, it seems other commands work the same as in master branch.

[tsmaeder]

The code changes look fine to me. As @azatsarynnyy has tested the changes, I'm fine with merging them.