toggle_layout action to zoom/unzoom active window

docs/changelog.rst

@@ -7,6 +7,8 @@ To update |kitty|, :doc:`follow the instructions <binary>`.
 0.21.3 [future]
 ----------------------
 
+- Add a new :ref:`action-toggle_layout` action to easily zoom/unzoom a window
+
 - Fix a bug in the implementation of the synchronized updates escape code that
   could cause incorrect parsing if either the pending buffer capacity or the
   pending timeout were exceeded (:iss:`3779`)

docs/kittens/custom.rst

@@ -103,7 +103,8 @@ terminal program, you can tell the kittens system to run the
 ``handle_result()`` function without first running the ``main()`` function.
 
 For example, here is a kitten that "zooms/unzooms" the current terminal window
-by switching to the stack layout or back to the previous layout.
+by switching to the stack layout or back to the previous layout. This is
+equivalent to the builtin :ref:`action-toggle_layout` action.
 
 Create a file in the kitty config folder, :file:`~/.config/kitty/zoom_toggle.py`