ipv6: simplify references to RFCs in package documentation

Change-Id: I8900190d3234d3f8883761b2ae735f2a959b9a26
Reviewed-on: https://go-review.googlesource.com/33252
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
1 file changed