Redis7 support for exising commands

Use NonEmpty list for all functions that requires it. User code
can migrate using OverloadedLists, though it doesn't play well
with overloaded list,.

Add documentation to the existing functions.

Author: qnikst

benchmark/Benchmark.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE OverloadedStrings, LambdaCase #-}
+{-# LANGUAGE OverloadedStrings, LambdaCase, OverloadedLists #-}
 
 module Main where