Remove `var ref` on `rpc` macro and just take ref

eth-rpc/server/servertypes.nim

@@ -44,7 +44,7 @@ proc hasReturnType(params: NimNode): bool =
   if params != nil and params.len > 0 and params[0] != nil and params[0].kind != nnkEmpty:
     result = true
 
-macro rpc*(server: var RpcServer, path: string, body: untyped): untyped =
+macro rpc*(server: RpcServer, path: string, body: untyped): untyped =
   result = newStmtList()
   let
     parameters = body.findChild(it.kind == nnkFormalParams)

tests/testserverclient.nim

@@ -5,7 +5,7 @@ var srv = newRpcServer()
 srv.address = "localhost"
 srv.port = Port(8545)
 
-proc makeProc(server: var RpcServer) =
+proc makeProc(server: RpcServer) =
   server.rpc("myProc") do(input: string, data: array[0..3, int]):
     result = %("Hello " & input & " data: " & $data)