Improve the &?ROUTINE section also with recursion example.

Author: fluca1978

doc/Language/variables.pod6

@@ -1078,11 +1078,29 @@ With particular regard to the C<$?NL>, see the  L<newline pragma|/language/pragm
 
 =head3 X<&?ROUTINE|&?ROUTINE>
 
-Which routine am I in? Has method C<.name>
+The compile time variable C<&?ROUTINE> provides introspection about
+which routine the program is actually within. It returns an instance
+of L<Sub|/type/Sub> attached to the current routine.
+It does support the method C<.name> to obtain
+the name of the called routine, as well as C<.signature> and others
+method related to C<Sub>:
+
 
     sub awesome-sub { say &?ROUTINE.name }
     awesome-sub # OUTPUT: awesome-sub
 
+The special variable C<&?ROUTINE> allows also for recursion:
+
+=begin code
+my $counter = 10;
+sub do-work {
+    say 'Calling myself other ' ~ $counter-- ~ ' times';
+    &?ROUTINE() if ( $counter > 0 );
+}
+do-work;
+=end code
+
+
 =begin code
 for '.' {
     .Str.say when !.IO.d;