Sane defaults for tmux with more visible statusbar

note, May 25, 2023 on Mitja Felicijan's blog

# Remap prefix from 'C-b' to 'M-a'.
@@ -27,21 +27,18 @@ set -g window-status-current-format "#[fg=#ffffff]#[bg=#111111]#[fg=#ffffff
 
 # Disable mouse mode (tmux 2.1 and above).
 set -g mouse off
-