Treat javascript: URL results as UTF-8 bytes

Closes #1129.

source

@@ -86533,13 +86533,13 @@ interface <dfn interface>Location</dfn> { // but see also <a href="#the-location
       <p>If <span data-x="js-Type">Type</span>(<var>result</var>) is String, then set
       <var>response</var> to a <span data-x="concept-response">response</span> whose <span
       data-x="concept-response-header-list">header list</span> consists of
-      `<code>Content-Type</code>`/`<code>text/html</code>`, and whose <span
-      data-x="concept-response-body">body</span> is <var>result</var>.</p>
+      `<code>Content-Type</code>`/`<code data-x="">text/html;charset=utf-8</code>`, and whose <span
+      data-x="concept-response-body">body</span> is the result of <span data-x="UTF-8 encode">UTF-8
+      encoding</span> <var>result</var>.</p>
 
-      <p class="XXX">The exact conversion between the string <var>result</var> and the bytes that
-      comprise a <span data-x="concept-response-body">response body</span> is not yet specified,
-      pending further investigation into user agent behavior. See <a
-      href="https://github.com/whatwg/html/issues/1129">issue #1129</a>.</p>
+      <p class="note">The encoding to UTF-8 means that unpaired <span
+      data-x="surrogate">surrogates</span> will not roundtrip, once the HTML parser decodes the
+      response body.</p>
      </li>
     </ol>
    </li>