effective_go.html: be more accepting in the guidelines for interface names Fixes issue 5421.
effective_go.html: be more accepting in the guidelines for interface names
Fixes issue 5421.

R=golang-dev, bradfitz, adg
CC=golang-dev
https://codereview.appspot.com/9274043

pombredanne/go-deleteme,apparentlymart/golang,gnanderson/go,apparentlymart/golang,gnanderson/go,apparentlymart/golang,gnanderson/go,apparentlymart/golang,apparentlymart/golang,tv42/old-go,apparentlymart/golang,dsriram/golang,pombredanne/go-deleteme,pombredanne/go-deleteme,tv42/old-go,tv42/old-go,gnanderson/go,dsriram/golang,dsriram/golang,tv42/old-go,pombredanne/go-deleteme,apparentlymart/golang,pombredanne/go-deleteme,tv42/old-go,gnanderson/go,gnanderson/go,dsriram/golang,pombredanne/go-deleteme,tv42/old-go,dsriram/golang,tv42/old-go,dsriram/golang,dsriram/golang,gnanderson/go,pombredanne/go-deleteme