doc: go1.6.txt: go test flag changes

Change-Id: Icb52589909776fbe195ef2502ec7c0a4b590f350
Reviewed-on: https://go-review.googlesource.com/14859
Reviewed-by: Rob Pike <r@golang.org>
diff --git a/doc/go1.6.txt b/doc/go1.6.txt
index 03ad32a..eb9ff14 100644
--- a/doc/go1.6.txt
+++ b/doc/go1.6.txt
@@ -1,6 +1,7 @@
 Tools:
 
 cmd/go: vendoring enabled by default (https://golang.org/cl/13967/)
+cmd/go: flags for tests must precede package name if present; also makes it easier to pass flags to test binaries (https://golang.org/cl/14826)
 
 Ports: