usage section in readme is elixir syntax

Author: the-mikedavis

README.md

@@ -10,21 +10,23 @@ Define the test suite for bless to run by making a list of tasks and
 arguments in your `mix.exs` file. Add a `:test_suite` key to the `project/0`
 function like so:
 
-    def project do
-      [
-        preferred_cli_env: [
-          bless: :test
-        ],
-        ..
-        test_suite: [
-          compile: ["--warnings-as-errors", "--force"],
-          "coveralls.html": [],
-          format: ["--check-formatted"],
-          credo: []
-        ],
-        ..
-      ]
-    end
+```elixir
+def project do
+  [
+    preferred_cli_env: [
+      bless: :test
+    ],
+    ..
+    test_suite: [
+      compile: ["--warnings-as-errors", "--force"],
+      "coveralls.html": [],
+      format: ["--check-formatted"],
+      credo: []
+    ],
+    ..
+  ]
+end
+```
 
 Then running `mix bless` will run each of those tasks.