RFC: Search field on accels window

The accels window displaying all the shortcuts available on the current view (open with hotkey h) is very useful. However, at least for me, it is sometimes not easy to quickly find the right shortcut in the list because of the many entries.
Therefore, I propose a simple search function on the window like shown in the following screenshot:

A new input field at the top center is introduced, where the user can enter a search string. Next to it, there is a button to start the search. As a result, all entries containing the entered search string are highlighted. In the example, the found entries are simply printed as bold. The search is a simple substring search.
The search field is only active and visible when the view is switched to sticky, as obviously only then entries can be made.

If there is a chance for this to be accepted, I would be happy to provide a PR.

Start by locating the accels window implementation and the code handling its sticky view, using hotkey h as the entry point. Confirm how shortcut entries are rendered, then define the search input and button behavior. Done means the field is visible only in sticky mode and substring matches are highlighted or shown in bold.