Fix the documentation for the initGRpc function (#156)

docs/docs/grpc.md

@@ -54,7 +54,7 @@ The simplest way to call methods is to use the `optics`-based API. In that case,
 ```haskell
 main :: IO ()
 main = do ...
-  where setup config = initGRpc config
+  where setup config = initGRpc config msgProtoBuf
 ```
 
 To call a method, you use the corresponding getter (for those familiar with optics, a version of a lens which does not allow to set). This means that your code reads `client ^. #method`, where `client` is the value obtained previously in the call to `initGRpc`.

grpc/client/src/Mu/GRpc/Client/Optics.hs

@@ -56,7 +56,7 @@ newtype GRpcConnection (s :: Package') (p :: GRpcMessageProtocol)
 --   inferred from the usage later on.
 --   However, it can also be made explicit by using
 --
---   > initGRpc config @Service
+--   > initGRpc config msgProtoBuf @Service
 --
 initGRpc :: G.GrpcClientConfig  -- ^ gRPC configuration
          -> Proxy p