tmux: Fix freezing when copying text.
tmux: Fix freezing when copying text.

The redirection to /dev/null is there to prevent freezing because xclip does
not close STDOUT after it has read from the tmux buffer (see
https://wiki.archlinux.org/index.php/Tmux#X_clipboard_integration).

s3rvac/dotfiles,s3rvac/dotfiles,s3rvac/dotfiles