add aliases for deadname mailmap stuff

git/.config/git/personal.gitconfig

@@ -10,6 +10,8 @@
 	sp = stash pop
 	sl = stash list
 	whoami = config --get-regexp '^user\\.'
+	list-identities = "!git log --all --pretty='%an <%ae>%n%cn <%ce>' | sort | uniq"
+	create-mailmap = "!f(){ git list-identities | sed \"s/^/$(echo $@) /\"; };f"
 
 # Rebase local commits on top of remote commits when running `git pull`
 [pull]