Improve key binding rendering

[colin-grant-work]

What it does

Fixes #10789 and fixes #5377 by using utilities from the keybinding registry to determine the shape of the rendered item. It also refactors the code to frontload the handling of fuzzy matching and not rebuild the whole list of keybinding candidates on every search. This entailed modifying the interfaces in the file so that the data maintained on the widget was a better input into the render cycle.

MacOS:

Ubuntu:

How to test

1. Open the keybinding widget.
2. Observe that the keys are rendered nicely (symbols on MacOS, capitalized keys without any ctrlcmd elsewhere).
3. Search for keybindings.
4. Observe that the results are as you expect, given our fuzzy implementation. In particular:
   • Observe that keys are only matched on a perfect matched
   • Observe that both + and whitespace can be used as term separators for keys

• 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

[vince-fugnitto]

I confirmed that the feature works for the most part, especially on macos 👍

• confirmed that on macos the key symbols are displayed but not their string values
• confirmed that updating keybinding will properly render afterwards
• confirmed that fuzzy matching still works

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I did notice an issue on Linux when using electron (the browser seems fine), the Escape keybinding rendering is broken:

[colin-grant-work]

@vince-fugnitto, good catch re: special characters in Electron. Esc, Delete, and Backspace appear to have special unicode characters that come from nativekeymap. I've added special handling in the method that generates the text representations for those values.

[vince-fugnitto]

The changes look good to me 👍
I confirmed that my previous feedback has been resolved.