json: longer description

Author: sorki

hnix-store-json/hnix-store-json.cabal

@@ -3,7 +3,7 @@ name:                hnix-store-json
 version:             0.1.0.0
 synopsis:            JSON serialization for core types
 description:
-  Aeson instances for core types
+  Aeson instances for core types, required for remote store protocol
 homepage:            https://github.com/haskell-nix/hnix-store
 license:             Apache-2.0
 license-file:        LICENSE