Add revisions to check_once docs

discord/ext/commands/bot.py

@@ -255,6 +255,12 @@ class BotBase(GroupMixin):
         bypasses that and ensures that it's called only once, even inside
         the default help command.
 
+        .. note::
+
+            When using this function the :class:`.Context` sent to a group subcommand
+            may only parse the parent command and not the subcommands due to it
+            being invoked once per :meth:`.Bot.invoke` call.
+
         .. note::
 
             This function can either be a regular function or a coroutine.

discord/ext/commands/cog.py

@@ -296,10 +296,6 @@ class Cog(metaclass=CogMeta):
         """A special method that registers as a :meth:`.Bot.check_once`
         check.
 
-        Note that when using this function, context sent from a group command
-        may only parse the parent command and not the subcommands due to it
-        being invoked once per :meth:`.Command.invoke` call.
-
         This function **can** be a coroutine and must take a sole parameter,
         ``ctx``, to represent the :class:`.Context`.
         """