fix(install): clarify chsh timings (#75)

Author: feliupe

Installing-ZSH.md

@@ -30,7 +30,7 @@ If necessary, follow these steps to install Zsh:
 
    - Note that this will not work if Zsh is not in your authorized shells list (`/etc/shells`)
      or if you don't have permission to use `chsh`. If that's the case [you'll need to use a different procedure](https://www.google.com/search?q=zsh+default+without+chsh).
-   - If you run just `chsh` you need to type `/bin/zsh` to make it your default shell.
+   - The new shell will only take place after you restart your computer - or run `/bin/zsh`.
 
 4. Log out and log back in again to use your new default shell.