Add custom status support (#6226)

Co-authored-by: Jakub Kuczys <me@jacken.men>

docs/cog_guides/core.rst

@@ -3769,6 +3769,35 @@ Maximum length for a competing status is 128 characters.
 **Arguments:**
     - ``[competing]`` - The text to follow ``Competing in``. Leave blank to clear the current activity status.
 
+.. _core-command-set-status-custom:
+
+"""""""""""""""""
+set status custom
+"""""""""""""""""
+
+.. note:: |owner-lock|
+
+**Syntax**
+
+.. code-block:: none
+
+    [p]set status custom [text]
+
+**Description**
+
+Sets Red's custom status.
+
+This will appear as ``<text>``.
+
+Maximum length for a custom status is 128 characters.
+
+**Examples:**
+    - ``[p]set status custom`` - Clears the activity status.
+    - ``[p]set status custom Running cogs...``
+
+**Arguments:**
+    - ``[text]`` - The custom status text. Leave blank to clear the current activity status.
+
 .. _core-command-set-status-dnd:
 
 """"""""""""""