Merge https://github.com/prati0100/git-gui

* https://github.com/prati0100/git-gui:
  git-gui: blame: prevent tool tips from sticking around after Command-Tab
  git-gui: improve dark mode support
  git-gui: fix mixed tabs and spaces; prefer tabs

diff --cc git-gui/git-gui.sh
Simple merge

diff --cc git-gui/lib/blame.tcl
Simple merge

diff --cc git-gui/lib/themed.tcl
Simple merge