doc/go1.16: add crypto/x509 note about Verify on Windows

Updates #42897

Change-Id: Ice25922475405aca3cf2cb1c163462f223ede736
Reviewed-on: https://go-review.googlesource.com/c/go/+/274239
Trust: Roland Shoemaker <roland@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>

Author: rolandshoemaker

doc/go1.16.html

@@ -416,7 +416,9 @@ <h3 id="minor_library_changes">Minor changes to the library</h3>
     </p>
 
     <p><!-- CL 257257 -->
-      TODO: <a href="https://golang.org/cl/257257">https://golang.org/cl/257257</a>: return additional chains from Verify on Windows
+      On Windows, <a href="/pkg/crypto/x509/#Certificate.Verify"><code>Certificate.Verify</code></a>
+      will now return all certificate chains that are built by the platform
+      certificate verifier, instead of just the highest ranked chain.
     </p>
 
     <p><!-- CL 262343 -->