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
net: fix dial race on plan9 and windows

Fixes issue 5349.

R=golang-dev, lucio.dere, dsymonds, bradfitz, iant, adg, dave, r
CC=golang-dev
https://codereview.appspot.com/9159043