name the exception on failed return type checks

doc/Language/control.pod6

@@ -665,7 +665,14 @@ All these forms may produce a return value the same way C<loop> does.
 
 =head1 X<return|control flow>
 
-The routine C<return> will stop execution of a subroutine or method, run all relevant L<phasers|/language/phasers#Block_Phasers> and provide the given return value to the caller. The default return value is C<Nil>. If a return L<type constraint|/type/Signature#Constraining_Return_Types> is provided it will be checked unless the return value is C<Nil>. A control exception is raised and can be caught with L<CONTROL|/language/phasers#CONTROL>.
+The routine C<return> will stop execution of a subroutine or method, run all
+relevant L<phasers|/language/phasers#Block_Phasers> and provide the given
+return value to the caller. The default return value is C<Nil>. If a return
+L<type constraint|/type/Signature#Constraining_Return_Types> is provided it
+will be checked unless the return value is C<Nil>. If the type check fails the
+exception L<X::TypeCheck::Return|/type/X::TypeCheck::Return> is thrown. If it
+passes a control exception is raised and can be caught with
+L<CONTROL|/language/phasers#CONTROL>.
 
 =comment TODO add link to section in /language/function that shows how return values are produces/handled