zshrc & gitconfig: use system vim

gitconfig

@@ -17,6 +17,7 @@
     lola = log --graph --decorate --pretty=oneline --abbrev-commit --all
     mnc = merge --no-commit
     oneline = log --oneline --decorate
+    pr = "!f() { git fetch origin pull/$1/head && git checkout FETCH_HEAD; }; f"
     pl = pull
     ps = push
     repourl = config --get remote.origin.url
@@ -69,7 +70,7 @@
     excludesfile = /Users/veitheller/.gitignore
     whitespace = space-before-tabmtrailing-space
     autocrlf = input
-    editor = /usr/local/bin/vim
+    editor = /usr/bin/vim
 
 [diff]
     tool = vimdiff