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

R=adg, dsymonds
CC=golang-dev
http://codereview.appspot.com/5319048

Committer: David Symonds <7f6bb564ed9e580d4f0aa90d53b34578e5d24cb9@golang.org>

h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang