keyboard_shortcuts: Add hotkeys for recent topics.

templates/zerver/app/keyboard_shortcuts.html

@@ -232,6 +232,23 @@
                 </tr>
             </table>
         </div>
+        <div>
+            <table class="hotkeys_table table table-striped table-bordered table-condensed">
+                <thead>
+                    <tr>
+                        <th colspan="2">{{ _("Recent topics") }}</th>
+                    </tr>
+                </thead>
+                <tr>
+                    <td class="definition">{% trans %}View recent topics{% endtrans %}</td>
+                    <td><span class="hotkey"><kbd>T</kbd></span></td>
+                </tr>
+                <tr>
+                    <td class="definition">{% trans %}Hide recent topics{% endtrans %}</td>
+                    <td><span class="hotkey"><kbd>Esc</kbd></span></td>
+                </tr>
+            </table>
+        </div>
         <div>
             <table class="hotkeys_table table table-striped table-bordered table-condensed">
                 <thead>

templates/zerver/help/keyboard-shortcuts.md

@@ -137,6 +137,14 @@ title="thumbs up"/>**: `+`
   (including All messages), and don't contribute to unread counts. Read more about
   [muting topics](/help/mute-a-topic).
 
+## Recent Topics
+
+* **View Recent Topics**: `t`
+* **Hide Recent Topics**: `Esc`
+
+Keyboard navigation (e.g. arrow keys) works as expected.
+Use `Enter` to engage with elements.
+
 ## Drafts
 
 * **Toggle drafts view**: `d`