help: Tweak docs on keyboard shortcuts for composing messages.

- Adjust the order in keyboard shortucts help menu and help center.
- Make minor wording improvements.

help/keyboard-shortcuts.md

@@ -100,21 +100,21 @@ in the Zulip app to add more to your repertoire as needed.
 
 ## Composing messages
 
-* **Reply to message**: <kbd>R</kbd> or <kbd>Enter</kbd> — Reply to the
-  selected message (outlined in blue). Same behavior as clicking on the
-  message.
-
-* **Reply to message, mentioning author**: <kbd>@</kbd>
-
-* **Reply only to author**: <kbd>Shift</kbd> + <kbd>R</kbd>
-
-* **Quote and reply to message**: <kbd>></kbd>
-
 * **New stream message**: <kbd>C</kbd> — For starting a new topic in a
   stream.
 
 * **New direct message**: <kbd>X</kbd>
 
+* **Reply to message**: <kbd>R</kbd> or <kbd>Enter</kbd> — Reply to the
+  selected message (outlined in blue). Same behavior as clicking on the
+  message.
+
+* **Quote and reply to message**: <kbd>></kbd>
+
+* **Reply directly to sender**: <kbd>Shift</kbd> + <kbd>R</kbd>
+
+* **Reply @-mentioning sender**: <kbd>@</kbd>
+
 ### In the compose box
 
 * **Send message**: <kbd>Enter</kbd>, <kbd>Tab</kbd> then <kbd>Enter</kbd>,

web/templates/keyboard_shortcuts.hbs

@@ -118,18 +118,6 @@
                         <th colspan="2">{{t 'Composing messages' }}</th>
                     </tr>
                 </thead>
-                <tr>
-                    <td class="definition">{{t 'Reply to message' }}</td>
-                    <td><span class="hotkey"><kbd>Enter</kbd> or <kbd>R</kbd></span></td>
-                </tr>
-                <tr>
-                    <td class="definition">{{t 'Reply to author' }}</td>
-                    <td><span class="hotkey"><kbd>Shift</kbd> + <kbd>R</kbd></span></td>
-                </tr>
-                <tr>
-                    <td class="definition">{{t 'Quote and reply to message' }}</td>
-                    <td><span class="hotkey"><kbd>></kbd></span></td>
-                </tr>
                 <tr>
                     <td class="definition">{{t 'New stream message' }}</td>
                     <td><span class="hotkey"><kbd>C</kbd></span></td>
@@ -139,7 +127,19 @@
                     <td><span class="hotkey"><kbd>X</kbd></span></td>
                 </tr>
                 <tr>
-                    <td class="definition">{{t 'Compose a reply @-mentioning author' }}</td>
+                    <td class="definition">{{t 'Reply to message' }}</td>
+                    <td><span class="hotkey"><kbd>Enter</kbd> or <kbd>R</kbd></span></td>
+                </tr>
+                <tr>
+                    <td class="definition">{{t 'Quote and reply to message' }}</td>
+                    <td><span class="hotkey"><kbd>></kbd></span></td>
+                </tr>
+                <tr>
+                    <td class="definition">{{t 'Reply directly to sender' }}</td>
+                    <td><span class="hotkey"><kbd>Shift</kbd> + <kbd>R</kbd></span></td>
+                </tr>
+                <tr>
+                    <td class="definition">{{t 'Reply @-mentioning sender' }}</td>
                     <td><span class="hotkey"><kbd>@</kbd></span></td>
                 </tr>
                 <tr>