Add missing 'instance Typeable HashMap'

Author: rockbmb

Data/HashMap/Base.hs

@@ -167,6 +167,7 @@ type role HashMapInner nominal representational
 -- | A wrapper over 'HashMapInner'. The 'Int' field represent the hashmap's
 -- size.
 data HashMap k v = HashMap {-# UNPACK #-} !Int !(HashMapInner k v)
+  deriving Typeable
 
 instance (NFData k, NFData v) => NFData (HashMapInner k v) where
     rnf Empty                 = ()