Revert "dont check colors (?)"

This reverts commit 103fe4e70370e3d78c36e36784471f1f787e44e8.

zshrc

@@ -4,7 +4,7 @@ source ~/.zsh_local
 
 # instantaneously start tmux, if available
 if command -v tmux>/dev/null; then
-  [ -z $TMUX ] && exec tmux new-session -A -s main
+  [[ ! $TERM =~ screen ]] && [ -z $TMUX ] && exec tmux new-session -A -s main
 fi
 
 # Source Prezto.