Feature Request: Return to last focused window on close

[jpfeltracco]

One thing I've noticed in Kitty is that focus doesn't seem to return to the last active window after a new window is closed. I have a use case for this using fzf in Kakoune with Kitty, where I spawn a new window for my query, then on enter the window closes and should jump back to the originating window.

Ex:

Start out with focus on the left
+---------------------+---------------------+
|                     |                     |
|                     |                     |
|                     |                     |
|                     |                     |
|                     |                     |
|       Focus         |                     |
|                     |                     |
|                     |                     |
|                     |                     |
|                     |                     |
|                     |                     |
|                     |                     |
+---------------------+---------------------+

Open a new window (fzf in Kakoune for example)
+---------------------+---------------------+
|                     |                     |
|                     |                     |
|                     |                     |
|                     |                     |
|                     |                     |
|                     +---------------------+
|                     |                     |
|                     |                     |
|                     |       Focus         |
|                     |                     |
|                     |                     |
|                     |                     |
+---------------------+---------------------+

On window close, focus goes to the "wrong" window, I have to manually 
move back to the originating window.
+---------------------+---------------------+
|                     |                     |
|                     |                     |
|                     |                     |
|                     |                     |
|                     |                     |
|                     |        Focus        |
|                     |                     |
|                     |                     |
|                     |                     |
|                     |                     |
|                     |                     |
|                     |                     |
+---------------------+---------------------+

This would be the ideal, going to the last active window after a window close.
+---------------------+---------------------+
|                     |                     |
|                     |                     |
|                     |                     |
|                     |                     |
|                     |                     |
|       Focus         |                     |
|                     |                     |
|                     |                     |
|                     |                     |
|                     |                     |
|                     |                     |
|                     |                     |
+---------------------+---------------------+

[elasticdog]

@kovidgoyal thank you so much for this fix and for all of your amazing work on kitty in general. I coincidentally had the same exact use case of Kakoune and fzf, and was going to file this same feature request. Looking forward to the 0.14.0 release!