doc: document CL330852 in changelog

This PR adds a note into the Go 1.18 changelog for CL330852 / #46923.

Author: neilalexander

doc/go1.18.html

@@ -165,6 +165,18 @@ <h3 id="minor_library_changes">Minor changes to the library</h3>
   </dd>
 </dl><!-- image/draw -->
 
+<dl id="net/http"><dt><a href="/pkg/net/http/">net/http</a></dt>
+  <dd>
+    <p><!-- CL 330852 -->
+      The <code>Dial</code>, <code>DialContext</code>, <code>DialTLS</code> and
+      <code>DialTLSContext</code> method fields in
+      <a href="/pkg/net/http#Transport"><code>http.Transport</code></a>
+      will now be correctly used, if specified, for making HTTP requests when running
+      on WebAssembly targets.
+    </p>
+  </dd>
+</dl><!-- net/http -->
+
 <dl id="reflect"><dt><a href="/pkg/reflect/">reflect</a></dt>
   <dd>
     <p><!-- CL 356049, 320929 -->