doc: GCC 6 will have the Go 1.6.1 user libraries

Update #14759.

Change-Id: I8a174aad721beb62380e10071d9648b6b1c21b8c
Reviewed-on: https://go-review.googlesource.com/22072
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Andrew Gerrand <adg@golang.org>

doc/go1.6.html

@@ -168,7 +168,7 @@ Go 1.7 will remove support for the old syntax.
 <p>
 The release schedules for the GCC and Go projects do not coincide.
 GCC release 5 contains the Go 1.4 version of gccgo.
-The next release, GCC 6, will have the Go 1.6 version of gccgo.
+The next release, GCC 6, will have the Go 1.6.1 version of gccgo.
 </p>
 
 <h3 id="go_command">Go command</h3>