doc: update go1.3.txt for regexp change
doc: update go1.3.txt for regexp change

LGTM=rsc
R=rsc
CC=golang-codereviews
https://codereview.appspot.com/72640043

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