Update README.md

Author: xx4h

README.md

@@ -210,7 +210,7 @@ You have edited `~/.tmux.conf` but no powerline is displayed. This might be beca
 ```shell
 tmux source-file ~/.tmux.conf
 ```
-### Multiple lines in bash or no powerline in zsh using iTerm (macOS)
+### Multiple lines in bash or no powerline in Zsh using iTerm (macOS)
 If your tmux looks like [this](https://github.com/erikw/tmux-powerline/issues/125) then you may have to in iTerm uncheck [Unicode East Asian Ambiguous characters are wide] in Preferences -> Settings -> Advanced.
 
 # Hacking