Docs - Fix "Change Hotkey Set" link

Author: david-cattermole

docs/source/tools_hotkeys.rst

@@ -142,8 +142,8 @@ the default Maya hotkeys.
 
 #. Edit the hotkeys using the Hotkey Editor.
 #. Press *Save and Close* button.
-#. Use the change-hotkey-set-heading_ button on the `mmSolver` shelf
-   to change the active Hotkey Set.
+#. Use the :ref:`Change Hotkey Set <change-hotkey-set-heading>` button
+   on the `mmSolver` shelf to change the active Hotkey Set.
 
 .. _Maya Zoom Pan tool:
    https://knowledge.autodesk.com/support/maya-lt/learn-explore/caas/CloudHelp/cloudhelp/2019/ENU/MayaLT-TextureBaking/files/GUID-A7CAE8D4-B3B0-4FF8-8405-4DF3427A8DB8-htm.html