misc/vim: "PACKAGE DOCUMENTATION" is not hilighted

R=golang-dev, r, dsymonds
CC=golang-dev
https://golang.org/cl/14018043

misc/vim/syntax/godoc.vim

@@ -7,7 +7,7 @@ if exists("b:current_syntax")
 endif
 
 syn case match
-syn match  godocTitle "^\([A-Z]*\)$"
+syn match  godocTitle "^\([A-Z][A-Z ]*\)$"
 
 command -nargs=+ HiLink hi def link <args>