docs: Add user guide for *Keyboard shortcuts* feature

templates/zerver/help/index.md

@@ -31,6 +31,7 @@ as a “**realm**”.
 - **[Posting and replying](#posting-and-replying)**
 - **[Searching](search-messages)**
 - **[Using emoji in messages](/help/emoji)**
+- **[Keyboard shortcuts](/help/keyboard-shortcuts)**
 - **[Mention a Team Member](/help/mention-a-team-member)**
 - **[Change Your Name](/help/name-change)**
 - **[Message formatting](/help/message-formatting)**

templates/zerver/help/keyboard-shortcuts.md

@@ -0,0 +1,38 @@
+# Keyboard Shortcuts
+Keyboard shortcuts allow a user to use Zulip easily and efficiently for a better user experience.
+
+Zulip keyboard shortcuts are divided into four categories:
+* [Navigation](#navigation)
+* [Composing messages](#composing-messages)
+* [Narrowing](#narrowing)
+* [Menus](#menus)
+
+## Navigation
+* **Initiate a search** `/` - This shortcut moves the user's cursor to the message search bar at the top of the window to allow them to begin searching for a messages belonging to a specific topic, stream, view, etc. in the realm.
+* **Search people** `q` - This shortcut moves the user's cursor to the user search bar in the right sidebar to to allow them to begin searching for a particular user in the realm.
+* **Search streams** `w` - This shortcut moves the user's cursor to the stream search bar in the left sidebar to to allow them to begin searching for a particular stream in the realm.
+* **Previous message** `k` `Up arrow` - This shortcut allows the user to scroll up to the previous message in their view.
+* **Next message** `j` `Down arrow` - This shortcut allows the user to scroll down to the next message in their view.
+* **Scroll up** `K` `PgUp` - This shortcut allows the user to scroll up through the messages in their view.
+* **Scroll down** `J` `PgDn` `Spacebar` - This shortcut allows the user to scroll down through the messages in their view.
+* **Last message** `End` - This shortcut allows the user to scroll to the most recent message in their view.
+
+## Composing messages
+* **Reply to message** `Enter` `r` - This shortcut allows the user to begin replying to the selected message (outlined in blue).
+* **Reply to author** `R` - This shortcut allows the user to begin writing a private message to the author of the selected message (outlined in blue).
+* **New stream message** `c` - This shortcut allows the user to begin composing a new stream message.
+* **New private message** `C` - This shortcut allows the user to begin composing a new stream message.
+* **Send message** `Tab key` then `Enter` - This shortcut allows the user to send the message that they've written.
+* **Cancel compose** `Esc` - This shortcut allows the user to cancel and discard their unsent message.
+
+## Narrowing
+* **Narrow by stream** `s` - This shortcut narrows the view to show all messages in the stream of the selected message (outlined in blue).
+* **Narrow by topic** `S` - This shortcut narrows the view to show all messages with the of the selected message (outlined in blue).
+* **Narrow to all private messages** `v` - This shortcut narrows the view to show all of the user's private messages.
+* **Cycle between stream narrows** `A` `D` - This shortcut allows the user to cycle through the narrows showing the messages of a stream according to Stream order in the left sidebar. `A` allows the user to navigate to the previous stream narrow, and `D` allows the user to navigate to the next stream narrow.
+* **Return to home view** `Esc` - This shortcut allows the user to return to the Home view, showing all messages in the realm.
+
+## Menus
+* **Open message actions menu** `i` - This shortcut shows the available message actions of the selected message (outlined in blue).
+* **Edit a message you sent** `i` then `Enter` - This shortcut allows the user to edit the selected message (outlined in blue) if the user authored the selected message. If the selected message was written by another user, this shortcut will enable the user to view the source code of the message.
+* **Show these keyboard shortcuts** `?` - This shortcut allows a modal window with a guide to all possible keyboard shortcuts to appear.