net/textproto: replace '3-digit' with 'three-digit'

A matter on form in documentation.

R=golang-dev, r
CC=golang-dev
https://codereview.appspot.com/13087043

Committer: Rob Pike <r@golang.org>
net/textproto: use ReadDotBytes instead of non-existent ReadDotAll.

Fixes issue 5893.

R=golang-dev, r
CC=golang-dev
https://codereview.appspot.com/13086043

Committer: Rob Pike <r@golang.org>