doc/go1.3.html: switch default stack size back to 8kB
doc/go1.3.html: switch default stack size back to 8kB

Update issue 8030

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://codereview.appspot.com/94680043

apparentlymart/golang,apparentlymart/golang,apparentlymart/golang,apparentlymart/golang,apparentlymart/golang,apparentlymart/golang,apparentlymart/golang