Closes #ISSUE

Fixed various issues and improved UX around the keystroke input
primarily when used for keystroke search.

Release Notes:

- Keymap Editor: FIxed an issue where the modifiers used to activate
keystroke search would appear in the keystroke search
- Keymap Editor: Made it possible to search for repeat modifiers, such
as a binding with `cmd-shift cmd`
- Keymap Editor: Made keystroke search matches match based on ordered
(not necessarily contiguous) runs. For example, searching for `cmd
shift-j` will match `cmd-k cmd-shift-j alt-q` and `cmd-i g shift-j` but
not `alt-k shift-j` or `cmd-k alt-j`
- Keymap Editor: Fixed the clear keystrokes binding (`delete` by
default) not working in the keystroke input