Add example for .multi

And mention the thing where &foo is a proto and its multi returns false

Author: zoffixznet

doc/Type/Routine.pod6

@@ -61,7 +61,14 @@ Returns the package in which the routine is defined.
 
     method multi(Routine:D: --> Bool:D)
 
-Returns C<True> if the routine is a multi sub or method.
+Returns C<True> if the routine is a multi sub or method. Note that
+the name of a multi sub refers to its proto and this method would
+return false if called on it. It needs to be called on the
+candidates themselves:
+
+    multi foo ($, $) {};
+    say &foo.multi # OUTPUT«False␤»
+    say &foo.candidates».multi # OUTPUT«(True)␤»
 
 =head2 method candidates