Add method Any.snitch in 6.e

This allows one to easily inspect a stage of a method call chain
on STDERR:

    $ raku -e 'use v6.*; (^10).grep(* %% 2).snitch.map(* ** 2).say'
    (0 2 4 6 8)
    (0 4 16 36 64)

src/core.e/Any-iterable-methods.pm6

@@ -16,6 +16,8 @@ augment class Any {
     multi method skip(*@skips) {
         self.skip(@skips)
     }
+
+    method snitch() { note self; self }
 }
 
 proto sub rotor(|) {*}