update README to reflect new default behavior

README.md

@@ -26,18 +26,16 @@ Fast JSON encoding and decoding for Clojure via the Jackson library.
 ## Encoding/Decoding Details
 
 `clj-json` can generate JSON for maps, vectors, lists, keywords, strings, integers, doubles, floats, and booleans.
-By default sets will be coerced into lists.
 
 Note that keywords generate as strings without a leading :, and will read via `parse-string` and `parsed-seq` as strings,
 however both have an optional boolean argument to keywordize the keys of maps.
-Namespaced keywords will encode to the form "namespace/keyword" by default.
 
 ## Redefining Coercions
 
 Coercions can be redefined by binding `*coercions*`. For example, to coerce sets into existence map:
 
 ```clojure
-(binding [clj-json.core/*coercions* {clojure.lang.IPersistentSet (fn [x] (reduce (fn [acc x] (assoc acc x true)) {} x))}]
+(binding [clj-json.core/*coercions* {clojure.lang.PersistentHashSet (fn [x] (reduce (fn [acc x] (assoc acc x true)) {} x))}]
   (is (= {"foo" {"bang" true, "bar" true}}
        (json/parse-string
         (json/generate-string {"foo" #{"bar" "bang"}})))))