Clarify keywords, symbols, maps, sets

resources/koans.clj

@@ -5,6 +5,9 @@
                       false
                       true
                       true
+                      false
+                      "foo"
+                      "foo"
                       3]}]
 
  ["02_lists" {"__" [1 2 3 4 5
@@ -31,15 +34,14 @@
                    [:butter :and]
                    3]}]
 
- ["04_sets" {"__" [nil
+ ["04_sets" {"__" [[3]
                 3
                 #{1 2 3 4 5}
                 #{1 2 3 4 5}
                 #{2 3}
                 #{1 4}]}]
 
- ["05_maps" {"__" [{}
-                0
+ ["05_maps" {"__" [:b 2
                 1
                 2
                 2