Add note about 4 finger gesture.

Author: therahedwig

reference_manual/preferences/canvas_only_mode.rst

@@ -1,5 +1,5 @@
 .. meta::
-   :description lang=en:
+   :description property=og\:description:
         Canvas only mode settings in Krita.
 
 .. metadata-placeholder
@@ -16,3 +16,7 @@ Canvas Only Mode
 ================
 
 Canvas Only mode is Krita's version of full screen mode. It is activated by hitting the :kbd:`Tab` key on the keyboard. Select which parts of Krita will be hidden in canvas-only mode -- The user can set which UI items will be hidden in canvas-only mode. Selected items will be hidden. 
+
+.. versionchanged:: 5.0
+
+   Canvas only-mode can also be entered by tapping the screen with 4 fingers.