Upstream changes from Trusted Types

See https://w3c.github.io/trusted-types/dist/spec/#integration-with-exec-command

Part of w3c/trusted-types#476

docs/execCommand/index.html

@@ -608,6 +608,17 @@ <h3 id="enabled-commands">
       <h2 id="methods-to-query-and-execute-commands">
         Methods to query and execute commands
       </h2>
+
+      <pre class="idl">
+        partial interface Document {
+          [CEReactions] boolean execCommand(DOMString commandId, optional boolean showUI = false, optional (DOMString or TrustedHTML) value = "");
+        };
+      </pre>
+
+      <p class="note">
+        TODO: Add IDL for queryCommand* functions.
+      </p>
+
       <p class="note">
         TODO: Define behavior for <var title="">show UI</var>.
       </p>
@@ -15208,6 +15219,17 @@ <h3>
         </p>
       </section>
     </section>
+    <section>
+      <h2 id="dependencies">
+        Dependencies
+      </h2>
+
+      The Trusted Types [[TRUSTED-TYPES]] specification defines:
+
+      <ul>
+        <li>The <dfn data-lt="TrustedHTML"><a href="https://w3c.github.io/trusted-types/dist/spec/#trustedhtml">TrustedHTML</a></dfn> IDL <a>interface</a>
+      </ul>
+    </section>
     <section>
       <h2 id="additional-requirements">
         Additional requirements