Update supervisor-and-application.markdown (elixir-lang#1314)

vsyrovat · José Valim · commit 0af219374eb6 · 2019-08-11T19:08:24.000+02:00
diff --git a/getting-started/mix-otp/supervisor-and-application.markdown b/getting-started/mix-otp/supervisor-and-application.markdown
@@ -236,6 +236,7 @@ Since we have specified `KV` as the module callback, let's change the `KV` modul
 defmodule KV do
   use Application
 
+  @impl true
   def start(_type, _args) do
     # Although we don't use the supervisor name below directly,
     # it can be useful when debugging or introspecting the system.
