Tree: filter is not discoverable

[isidorn]

I think that the tree filtering is not discoverable, especially in trees where people do not expect it to work. Like Call Stack, Watch...
Here's what I propose:

1. Render the orange filter widget with a minimal width when the tree has focus
2. Hovering over the minimal width filter widget we show a message "Start typing to filter"
3. When the user hides the minimal width widget, we no longer show it when empty for that tree.

[vscodebot]

This issue is being closed to keep the number of issues in our inbox on a manageable level, we are closing issues that are not going to be addressed in the foreseeable future: We look at the number of votes the issue has received and the number of duplicate issues filed. More details here. If you disagree and feel that this issue is crucial: We are happy to listen and to reconsider.

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Thanks for your understanding and happy coding!

[usernamehw]

A bit similar to #70646

[joaomoreno]

Thanks for the ping @usernamehw. You might have realized we're in a cleanup iteration right now and closing issues. I will actually close the other issue and keep this open to address the filter discoverability, which you mention in #70646. I understand that you actually request more functionality in that issue, but out of cleanup sake, I'll close the issue as won't fix. Note that some of that functionality is spread out in other issues, like #59455

[joaomoreno]

Dupe of #70646