misc/vim: Add rune keyword
According to adding rune type

R=adg, dsymonds
CC=golang-dev
https://golang.org/cl/5319048
diff --git a/misc/vim/syntax/go.vim b/misc/vim/syntax/go.vim
index 7ede9d5..7c17534 100644
--- a/misc/vim/syntax/go.vim
+++ b/misc/vim/syntax/go.vim
@@ -68,7 +68,7 @@
 
 " Predefined types
 syn keyword     goType              chan map bool string
-syn keyword     goSignedInts        int int8 int16 int32 int64
+syn keyword     goSignedInts        int int8 int16 int32 int64 rune
 syn keyword     goUnsignedInts      byte uint uint8 uint16 uint32 uint64 uintptr
 syn keyword     goFloats            float32 float64
 syn keyword     goComplexes         complex64 complex128