Quote \ so that tmux 3.0 works
Quote \ so that tmux 3.0 works

Per tmux 3.0 changelog:
* INCOMPATIBLE: tmux's configuration parsing has changed to use yacc(1). There
  is one incompatible change: a \ on its own must be escaped or quoted as
  either \\ or '\' (the latter works on older tmux versions).

larrylv/dotfiles,larrylv/dotfiles