update hotkeys docs

docs/plugins/hotkeys.rst

@@ -2,7 +2,7 @@ hotkeys
 =======
 
 .. dfhack-tool::
-    :summary: Show all dfhack keybindings for the current context.
+    :summary: Show all DFHack keybindings for the current context.
     :tags: dfhack
 
 The command opens an in-game screen showing which DFHack keybindings are active
@@ -11,8 +11,22 @@ in the current context. See also `hotkey-notes`.
 Usage
 -----
 
-::
+``hotkeys``
+    Show the list of keybindings for the current context in an in-game menu.
+``hotkeys list``
+    List the keybindings to the console.
 
-    hotkeys
+Menu overlay widget
+-------------------
 
-.. image:: ../images/hotkeys.png
+The in-game hotkeys menu is registered with the `overlay` framework and can be
+enabled as a hotspot in the upper-left corner of the screen. You can bring up
+the menu by hovering the mouse cursor over the hotspot and can select a command
+to run from the list by clicking on it with the mouse or by using the keyboard
+to select a command with the arrow keys and hitting :kbd:`Enter`.
+
+A short description of the command will appear in a nearby textbox. If you'd
+like to see the full help text for the command or edit the command before
+running, you can open it for editing in `gui/launcher` by right clicking on the
+command, left clicking on the arrow to the left of the command, or by pressing
+the right arrow key while the command is selected.