HTML validation: Fix problems with tag nesting.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

templates/zerver/api/configuring-python-bindings.md

@@ -42,7 +42,7 @@ can be found in the following table:
         <td>Yes</td>
         <td>
             <a href="/api/api-keys">API key</a>, which you can get through
-            Zulip's web interface.</a>
+            Zulip's web interface.
         </td>
     </tr>
     <tr>

templates/zerver/app/search_operators.html

@@ -40,11 +40,11 @@
                 <td class="operator">id:<span class="operator_value">id</span></td>
                 <td class="definition">{{ _('Narrow to just message ID') }} <span class="operator_value">id</span></td>
             </tr>
-            <tr>
             <tr>
                 <td class="operator">is:alerted</td>
                 <td class="definition">{{ _('Narrow to messages with alert words.') }}</td>
             </tr>
+            <tr>
                 <td class="operator">is:mentioned</td>
                 <td class="definition">{{ _('Narrow to messages that mention you.') }}</td>
             </tr>