Mention/index return-rw

Closes #453

Author: zoffixznet

doc/Language/control.pod

@@ -680,6 +680,10 @@ All these forms may produce a return value the same way C<loop> does.
 
 =comment TODO
 
+=head1 X<return-rw|control flow>
+
+Same as C<return>, but returns a writable container.
+
 =head1 X<once|control flow>
 
 A block prefix with C<once> will be executed exactly once, even if placed inside a

doc/Type/Routine.pod

@@ -156,7 +156,7 @@ produces
 =end code
 
 Note that C<return> marks return values as read only; if you need an early
-exit from an C<is rw> routine, you have to use C<return-rw> instead.
+exit from an C<is rw> routine, you have to use X<C<return-rw>|return-rw> instead.
 
 =head2 trait is export