doc: how to configure the JSON library

README.md

@@ -231,14 +231,19 @@ iex> Fiz.Foo.json_decode("{\"a\":42}")
 iex> Fiz.Foo.json_decode!("{\"a\":42}")
 ```
 
-
 ### JSON library configuration
 
-By default, `protox` uses [`Jason`](https://github.com/michalmuskala/jason) to encode values to JSON (mostly to escape strings). You can also use [`Poison`](https://github.com/devinus/poison):
+By default, `protox` uses [`Jason`](https://github.com/michalmuskala/jason) to encode values to JSON. You can also use [`Poison`](https://github.com/devinus/poison) by configuring the `json_library` option:
 
 ```elixir
-iex> Protox.json_decode!(iodata, Fiz.Foo, json_library: Protox.Poison)
-iex> Protox.json_encode!(msg, json_library: Protox.Poison)
+defmodule MyModule do
+  use Protox, schema: """
+  syntax = "proto3";
+
+  message Foo {}
+  """,
+  json_library: Poison # or Jason
+end
 ```
 
 ℹ️ You can use any other library by implementing the `Protox.JsonLibrary` behaviour.

lib/protox.ex

@@ -157,9 +157,6 @@ defmodule Protox do
   ## Errors
   This function returns a tuple `{:error, reason}` if:
   - `input` could not be decoded to JSON; `reason` is a `Protox.JsonDecodingError` error
-
-  ## JSON library configuration
-  TODO: document json library configuration
   """
   @doc since: "2.0.0"
   @spec json_decode(iodata(), atom()) :: {:ok, struct()} | {:error, any()}
@@ -198,13 +195,6 @@ defmodule Protox do
       iex> {:ok, iodata} = msg |> Protox.json_encode()
       iex> :binary.list_to_bin(iodata)
       "{\\"msgK\\":{\\"2\\":\\"bar\\",\\"1\\":\\"foo\\"}}"
-
-  ## JSON library configuration
-  TODO: document the json library configuration
-
-  ## Encoding specifications
-  See https://developers.google.com/protocol-buffers/docs/proto3#json for the specifications
-  of the encoding.
   """
   @doc since: "2.0.0"
   @spec json_encode(struct()) :: {:ok, iodata()} | {:error, any()}