basic/hashmap,set: move pointer symbol adjactent to the returned value

I think this is nicer in general, and here in particular we have a lot
of code like:
 static inline IteratedCache* hashmap_iterated_cache_new(Hashmap *h) {
         return (IteratedCache*) _hashmap_iterated_cache_new(HASHMAP_BASE(h));
 }
and it's visually appealing to use the same whitespace in the function
signature and the cast in the body of the function.