Improve language in haddocks for Data.HashMap.compose (#500)

Mirroring haskell/containers#1143

Author: alexfmpe

Data/HashMap/Internal.hs

@@ -1731,9 +1731,8 @@ unions = List.foldl' union empty
 ------------------------------------------------------------------------
 -- * Compose
 
--- | Relate the keys of one map to the values of
--- the other, by using the values of the former as keys for lookups
--- in the latter.
+-- | Given maps @bc@ and @ab@, relate the keys of @ab@ to the values of @bc@,
+-- by using the values of @ab@ as keys for lookups in @bc@.
 --
 -- Complexity: \( O (n * \log(m)) \), where \(m\) is the size of the first argument
 --