Simplify `mux` usage of `tmux send-keys`
Simplify `mux` usage of `tmux send-keys`

Previously doing some weird acrobatics with key escaping. Turns out the
only thing unusual is when the sequence of keys ends with `;`.

benizi/dotfiles,benizi/dotfiles,benizi/dotfiles,benizi/dotfiles,benizi/dotfiles,benizi/dotfiles,benizi/dotfiles,benizi/dotfiles