Mention that account might still be required in doc for feeless if. (#…

…6490)

Co-authored-by: Bastian Köcher <git@kchr.de>

substrate/frame/support/src/lib.rs

@@ -1883,11 +1883,16 @@ pub mod pallet_macros {
 	/// }
 	/// ```
 	///
-	/// Please note that this only works for signed dispatchables and requires a signed
+	/// Please note that this only works for signed dispatchables and requires a transaction
 	/// extension such as [`pallet_skip_feeless_payment::SkipCheckIfFeeless`] to wrap the
 	/// existing payment extension. Else, this is completely ignored and the dispatchable is
 	/// still charged.
 	///
+	/// Also this will not allow accountless caller to send a transaction if some transaction
+	/// extension such as `frame_system::CheckNonce` is used.
+	/// Extensions such as `frame_system::CheckNonce` require a funded account to validate
+	/// the transaction.
+	///
 	/// ### Macro expansion
 	///
 	/// The macro implements the [`pallet_skip_feeless_payment::CheckIfFeeless`] trait on the