Document Mu.WHERE

Author: paultcochrane

lib/Type/Mu.pod

@@ -137,6 +137,12 @@ Returns an object of type L<ObjAt> which uniquely identifies the object.
 Value types override this method which makes sure that two equivalent objects
 return the same return value from C<WHICH>.
 
+=head2 method WHERE
+
+    method WHERE() returns Int
+
+Returns an C<Int> representing the memory address of the object.
+
 =head2 trait is export
 
     multi sub trait_mod:<is>(Mu:U \type, :$export!)