increase the target files for formatting

.formatter.exs

@@ -1,5 +1,6 @@
 [
   inputs: [
-    "lib/**/*.{ex,exs}"
+    "{mix,.formatter}.exs",
+    "{config,lib}/**/*.{ex,exs}"
   ]
 ]

mix.exs

@@ -2,18 +2,20 @@ defmodule PowerAssert.MixProject do
   use Mix.Project
 
   def project do
-    [app: :power_assert,
-     version: "0.2.1",
-     elixir: "~> 1.6",
-     description: "Power Assert in Elixir. Shows evaluation results each expression.",
-     package: [
-       maintainers: ["Takayuki Matsubara"],
-       licenses: ["Apache 2.0"],
-       links: %{"GitHub" => "https://github.com/ma2gedev/power_assert_ex"}
-     ],
-     build_embedded: Mix.env == :prod,
-     start_permanent: Mix.env == :prod,
-     deps: deps()]
+    [
+      app: :power_assert,
+      version: "0.2.1",
+      elixir: "~> 1.6",
+      description: "Power Assert in Elixir. Shows evaluation results each expression.",
+      package: [
+        maintainers: ["Takayuki Matsubara"],
+        licenses: ["Apache 2.0"],
+        links: %{"GitHub" => "https://github.com/ma2gedev/power_assert_ex"}
+      ],
+      build_embedded: Mix.env() == :prod,
+      start_permanent: Mix.env() == :prod,
+      deps: deps()
+    ]
   end
 
   # Configuration for the OTP application
@@ -33,7 +35,9 @@ defmodule PowerAssert.MixProject do
   #
   # Type `mix help deps` for more examples and options
   defp deps do
-    [{:ex_spec, ">= 2.0.0", only: :test},
-     {:ex_doc, ">= 0.0.0", only: :dev}]
+    [
+      {:ex_spec, ">= 2.0.0", only: :test},
+      {:ex_doc, ">= 0.0.0", only: :dev}
+    ]
   end
 end