Change how I add the `vcs_info` function call to the `precmd` hook.
Using add-zsh-hook allows me to have multiple hook functions on `precmd`
and makes it clear what is done for each hook when listing them
Moved the setTermTitle function call out of the prompt line and into the
precmd hook.
This shortens the non-visible length of the prompt line and also makes
the functionality clearer
