git: add git revert alias (#7841)

* git: add `alias grev="git revert"`

* Swapping double for single quotes

Matching the conventions in the plugin

plugins/git/git.plugin.zsh

@@ -199,6 +199,7 @@ alias grbd='git rebase develop'
 alias grbi='git rebase -i'
 alias grbm='git rebase master'
 alias grbs='git rebase --skip'
+alias grev='git revert'
 alias grh='git reset'
 alias grhh='git reset --hard'
 alias groh='git reset origin/$(git_current_branch) --hard'