Add references for license (#286)

Author: solar05

README.md

@@ -38,4 +38,5 @@ end
 
 ## License
 
-Same as Elixir.
+Same as Elixir under Apache License 2.0.
+Check [NOTICE](https://github.com/elixir-lang/elixir/blob/main/NOTICE) and [LICENSE](https://github.com/elixir-lang/elixir/blob/main/LICENSE) for more information.

examples/gen_event.exs

@@ -2,7 +2,7 @@
 defmodule Broadcaster do
   @moduledoc """
   Using a GenStage for implementing a GenEvent manager
-  replacement where each handler runs as a separate process.
+  replacement, where each handler runs as a separate process.
   It is around 40 LOC without docs and comments.
 
   This implementation will keep events in an internal queue