doc/go1.5.txt: mention that testing/quick now generates nil pointers.

Change-Id: I358b17304f95fdd8e6c0a64fa29f185c701fe338
Reviewed-on: https://go-review.googlesource.com/10805Reviewed-by: Andrew Gerrand <adg@golang.org>

doc/go1.5.txt

@@ -77,6 +77,7 @@ strings: add Compare(x, y string) int, for symmetry with bytes.Compare (https://
 syscall: Add Foreground and Pgid to SysProcAttr (https://golang.org/cl/5130)
 syscall: add missing Syscall9 for darwin/amd64 (https://golang.org/cl/6555)
 testing/quick: support generation of arrays (https://golang.org/cl/3865)
+testing/quick: generated pointers can now be nil (https://golang.org/cl/10821)
 text/template: add Options method (https://golang.org/cl/8462)
 text/template: huge integers are now parse errors (https://golang.org/cl/9651)
 time: add time.AppendFormat(https://golang.org/cl/1760)