src: Restore the window title when quitting or suspending Kakoune.
src: Restore the window title when quitting or suspending Kakoune.

Fixes #4228.

casimir/kakoune,mawww/kakoune,lenormf/kakoune,alexherbo2/kakoune,alexherbo2/kakoune,jkonecny12/kakoune,casimir/kakoune,mawww/kakoune,mawww/kakoune,jkonecny12/kakoune,jkonecny12/kakoune,lenormf/kakoune,lenormf/kakoune,casimir/kakoune,casimir/kakoune,jkonecny12/kakoune,lenormf/kakoune,alexherbo2/kakoune,alexherbo2/kakoune,mawww/kakoune