gitconfig: fix git pr

gitconfig

@@ -14,7 +14,7 @@
     lgp = log --pretty=format:'%Cred%h%Creset -- %cn, %cr\t%Cgreen%s%Creset'
     lol = log --graph --decorate --pretty=oneline --abbrev-commit
     lola = log --graph --decorate --pretty=oneline --abbrev-commit --all
-    pr = "!f() { git fetch origin pull/$1/head && git checkout FETCH_HEAD; }; f"
+    pr = "!f() { git fetch -fu ${2:-origin} refs/pull/$1/head && git checkout FETCH_HEAD; }; f"
     pl = pull
     ps = push
     repourl = config --get remote.origin.url