git: add the `git show` alias `gsh` (#5591)

plugins/git/git.plugin.zsh

@@ -226,6 +226,7 @@ alias grv='git remote -v'
 
 alias gsb='git status -sb'
 alias gsd='git svn dcommit'
+alias gsh='git show'
 alias gsi='git submodule init'
 alias gsps='git show --pretty=short --show-signature'
 alias gsr='git svn rebase'