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

Update #8030

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/94680043

doc/go1.3.html

@@ -285,10 +285,6 @@ Significant instances include:
 
 <ul> 
 
-<li>
-As mentioned above, the default stack size has been reduced from 8 kilobytes to 4 kilobytes.
-</li>
-
 <li>
 The runtime handles defers more efficiently, reducing the memory footprint by about two kilobytes
 per goroutine that calls defer.