Enhancement request: allow the user to more finely control the behavior of the Search hotkey

[hackerTiger21]

With the keyboard shortcuts of vanilla e621, the cursor automatically moves to the end of the typed query, whereas re621's version of the same shortcut moves the cursor to the beginning. As re621 disables the vanilla shortcuts entirely, it's quite a hassle to have to move the cursor all the way back to the front.

I'd like to propose an option that would fit very well in the Sidebar sub-menu of the General tab, it can be a simple on/off checkbox like the rest of the options. By default, the option is off and a non-mouse event that focuses the search bar, i.e. auto-focus or a keyboard shortcut, would set the cursor to the leftmost position. Conversely, having the option turned on would make it so that the cursor snaps to the rightmost position of the current string, like it does in vanilla e621.