lib: follow standards in window title (#9320)

In Ubuntu and Debian, in scp, and in rsync the prompt is by default specified as in

  user@hostname:/path/to/directory

while the previous title in ohmyzsh was

  user@hostname: /path/to/directory

lib/termsupport.zsh

@@ -42,7 +42,7 @@ function title {
 }
 
 ZSH_THEME_TERM_TAB_TITLE_IDLE="%15<..<%~%<<" #15 char left truncated PWD
-ZSH_THEME_TERM_TITLE_IDLE="%n@%m: %~"
+ZSH_THEME_TERM_TITLE_IDLE="%n@%m:%~"
 # Avoid duplication of directory in terminals with independent dir display
 if [[ "$TERM_PROGRAM" == Apple_Terminal ]]; then
   ZSH_THEME_TERM_TITLE_IDLE="%n@%m"