Fix my very very silly mistake of makeing keys and values the same type in map, also add a map.for_each function

tests/test_map.expected_results

@@ -6,3 +6,8 @@
 2
 30
 4
+Lookie, a map!
+What I get for not testing different types
+key: 7, value: Lookie, a map!
+key: 20, value: What I get for not testing different types
+key: 30, value: we'll look for for_each too