user docs: Dynamically replace keyboard shortcuts for Mac OS.

static/js/portico/help.js

@@ -29,12 +29,44 @@ function highlight_current_article() {
     article.addClass('highlighted');
 }
 
+function adjust_mac_shortcuts() {
+    var keys_map = new Map([
+        ['Backspace', 'Delete'],
+        ['Enter', 'Return'],
+        ['Home', 'Fn + ⇽'],
+        ['End', 'Fn + ⇾'],
+        ['PgUp', 'Fn + ↑'],
+        ['PgDn', 'Fn + ↓'],
+    ]);
+
+    $(".markdown .content code").each(function () {
+        var text = $(this).text();
+
+        if (!keys_map.has(text)) {
+            return;
+        }
+
+        var key_string = keys_map.get(text);
+        var keys = key_string.match(/[^\s\+]+/g);
+
+        _.each(keys, function (key) {
+            key_string = key_string.replace(key, '<code>' + key + '</code>');
+        });
+
+        $(this).replaceWith(key_string);
+    });
+}
+
 function render_code_sections() {
     $(".code-section").each(function () {
         registerCodeSection($(this));
     });
 
     highlight_current_article();
+
+    if (/Mac/i.test(navigator.userAgent)) {
+        adjust_mac_shortcuts();
+    }
 }
 
 (function () {

templates/zerver/help/getting-started-with-zulip.md

@@ -55,4 +55,4 @@ Once you've figured out the basics, you'll probably want to:
   interest.
 - Master Zulip's [keyboard shortcuts](/help/keyboard-shortcuts). Anything
   you can do with the mouse, you can do even faster from the keyboard. Start
-  with `n`, `↓`, `c`, and `Enter` (`Return`), and use `?` for help.
+  with `n`, `↓`, `c`, and `Enter`, and use `?` for help.

templates/zerver/help/keyboard-shortcuts.md

@@ -13,11 +13,6 @@ below, and add more to your repertoire as needed.
 * [Menus](#menus)
 * [Streams settings](#streams-settings-page)
 
-!!! warn ""
-    Replace `Enter` with `Return` if using a Mac keyboard.
-
-    Other Mac shortcuts are shown in parentheses when different.
-
 ## The basics
 
 * **Reply to message**: `r` or `Enter` — Reply to the selected
@@ -35,7 +30,7 @@ below, and add more to your repertoire as needed.
 
 * **Next message**: `↓` or `j`
 
-* **Last message**: `End` (`Fn` + `⇾`) or `G` — Also marks all messages in
+* **Last message**: `End` or `G` — Also marks all messages in
   the current view as read.
 
 * **Next unread topic**: `n`
@@ -54,18 +49,18 @@ below, and add more to your repertoire as needed.
 
 * **Search people**: `w`
 
-* **Last message**: `End` (`Fn` + `⇾`) or `G` — Also marks all messages in
+* **Last message**: `End` or `G` — Also marks all messages in
   the current view as read.
 
-* **First message**: `Home` (`Fn` + `⇽`)
+* **First message**: `Home`
 
 * **Previous message**: `↑` or `k`
 
 * **Next message**: `↓` or `j`
 
-* **Scroll up**: `PgUp` (`Fn` + `↑`) or `K`
+* **Scroll up**: `PgUp` or `K`
 
-* **Scroll down**: `PgDn` (`Fn` + `↓`), `J`, or `Spacebar`
+* **Scroll down**: `PgDn`, `J`, or `Spacebar`
 
 ## Narrowing
 
@@ -83,7 +78,7 @@ below, and add more to your repertoire as needed.
 
 ## Composing messages
 
-* **Reply to message**: `r` or `Enter` (`Return`) — Reply to the selected
+* **Reply to message**: `r` or `Enter` — Reply to the selected
   message (outlined in blue). Same behavior as clicking on the message.
 
 * **Reply to message, mentioning author**: `@`
@@ -140,7 +135,7 @@ title="thumbs up"/>**: `+`
 
 * **Edit selected draft**: `Enter`
 
-* **Delete selected draft**: `Backspace` (`Delete`)
+* **Delete selected draft**: `Backspace`
 
 Keyboard navigation (e.g. arrow keys) works as expected.