vim: "ref" and "static" are now keywords; highlight them as such

Author: pcwalton

src/etc/vim/syntax/rust.vim

@@ -16,7 +16,7 @@ syn keyword   rustKeyword     alt again as break
 syn keyword   rustKeyword     check claim const copy do drop else export extern fail
 syn keyword   rustKeyword     for if impl import in let log
 syn keyword   rustKeyword     loop match mod module move mut new of owned priv pub pure
-syn keyword   rustKeyword     ret return to unchecked
+syn keyword   rustKeyword     ref ret return static to unchecked
 syn match     rustKeyword     "unsafe" " Allows also matching unsafe::foo()
 syn keyword   rustKeyword     use while with
 " FIXME: Scoped impl's name is also fallen in this category