doc/go1.14: mention new field net/http/httptest/Server.EnableHTTP2

Updates #34939
Updates #36878

Change-Id: Ifa9a17b5b16bfcfbfe1d113a2b66a63ea3a6b59c
Reviewed-on: https://go-review.googlesource.com/c/go/+/217131
Reviewed-by: Brad Fitzpatrick <[email protected]>

Author: ianlancetaylor

doc/go1.14.html

@@ -532,6 +532,17 @@ <h2 id="library">Core library</h2>
 
 </dl><!-- math/big -->
 
+<dl id="net/http/httptest"><dt><a href="/net/http/httptest/">net/http/httptest</a></dt>
+  <dd>
+    <p><!-- CL 201557 -->
+      The
+      new <a href="/pkg/net/http/httptest/#Server"><code>Server</code></a>
+      field <a href="/pkg/net/http/httptest/#Server.EnableHTTP2"><code>EnableHTTP2</code></a>
+      supports enabling HTTP/2 on the test server.
+    </p>
+  </dd>
+</dl><!-- net/http/httptest -->
+
 <dl id="plugin"><dt><a href="/pkg/plugin/">plugin</a></dt>
   <dd>
     <p><!-- CL 191617 -->