doc/go1.16: reference misc/ios/README for how to build iOS programs

Updates #43371, #43343.

Change-Id: Ib89b809a5220717507272453ea86224d1928dd36
Reviewed-on: https://go-review.googlesource.com/c/go/+/280154
Trust: Cherry Zhang <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>

Author: cherrymui

doc/go1.16.html

@@ -55,7 +55,9 @@ <h3 id="darwin">Darwin and iOS</h3>
   Go 1.16 adds an <code>ios/amd64</code> port, which targets the iOS
   simulator running on AMD64-based macOS. Previously this was
   unofficially supported through <code>darwin/amd64</code> with
-  the <code>ios</code> build tag set.
+  the <code>ios</code> build tag set. See also
+  <a href="/misc/ios/README"><code>misc/ios/README</code></a> for
+  details about how to build programs for iOS and iOS simulator.
 </p>
 
 <p><!-- golang.org/issue/23011 -->