Remove Any.reduce.

Apparently there is no method reduce in Any:

Any.reduce;
Cannot resolve caller reduce(Any: ); none of these signatures match:
    ($: &with, *%_)

This should not hurt, since reduce was marked as a TODO item.

Documentation comes from the source of Any shipped with
Rakudo version 2017.11 built on MoarVM version 2017.11

See issue #1731

doc/Type/Any.pod6

@@ -658,13 +658,6 @@ L«C<List.squish>|/type/List#routine_squish» on it.
 
     say Any.squish; # OUTPUT: «((Any))␤»
 
-=head2 method reduce
-
-Defined As:
-
-    method reduce(&with --> Nil)
-
-TODO
 
 =head2 method permutations