Change search shortcut behavior to be more intuitive

Change search shortcut to a new focus-search action to always refocus on search bar instead of closing it if it's already open. It still can be closed by pressing the clear button, backspace, search button, or Escape key.

Change the focus-search action behavior to select all text when a search refocusing action occurs so it's easier to type a new query.

Fixes #2819 (closed)