[release-branch.go1.9] doc: document Go 1.9.6

Change-Id: I9699b22d3a308cda685aa684b32dcde99333df46
Reviewed-on: https://go-review.googlesource.com/110315
Reviewed-by: Filippo Valsorda <filippo@golang.org>
(cherry picked from commit 40685b230a012dd5a9ca471dbf21b65457c32147)
Reviewed-on: https://go-review.googlesource.com/110375
Reviewed-by: Andrew Bonventre <andybons@golang.org>
diff --git a/doc/devel/release.html b/doc/devel/release.html
index cc481fd..5fe6a0e 100644
--- a/doc/devel/release.html
+++ b/doc/devel/release.html
@@ -70,6 +70,13 @@
 1.9.5 milestone</a> on our issue tracker for details.
 </p>
 
+<p>
+go1.9.6 (released 2018/05/01) includes fixes to the compiler and go command.
+See the <a href="https://github.com/golang/go/issues?q=milestone%3AGo1.9.6">Go
+1.9.6 milestone</a> on our issue tracker for details.
+</p>
+
+
 <h2 id="go1.8">go1.8 (released 2017/02/16)</h2>
 
 <p>