chore(shell): add a checkpoint commit alias

When working on the start of a project its nice to know what you are
changing. Or when you are working on a refactor having points to get
back to is nice. When we are done we can go and clean up the history so
it makes sense, for review, or just give our points more descriptive
messages and you don't need to brake your flow when coding.

site-modules/core/files/oh-my-zsh/custom/git.zsh

@@ -5,6 +5,7 @@ alias gml="git merge --log"
 alias gl="git --no-pager log --format=\"%C(red)%h%Creset %s %Cgreen(%cr)%Creset %C(bold blue)<%an>%Creset\" --reverse --max-count=40"
 alias gap="git add -p"
 alias gs="gss"
+alias checkpoint="git commit -m 'fixup: checkpoint'"
 
 function git_get_fetch_url() {
     git remote show origin -n | awk '/Fetch URL:/{print $3}'