Tweak service provider code style

src/Jenssegers/Mongodb/MongodbServiceProvider.php

@@ -14,6 +14,7 @@ class MongodbServiceProvider extends ServiceProvider {
     public function boot()
     {
         Model::setConnectionResolver($this->app['db']);
+
         Model::setEventDispatcher($this->app['events']);
     }
 
@@ -24,8 +25,10 @@ class MongodbServiceProvider extends ServiceProvider {
      */
     public function register()
     {
-        // Add a mongodb extension to the original database manager
-        $this->app->resolving('db', function($db) {
+        // Add a mongodb extension to the original database manager,
+        // when the database instance is being resolved.
+        $this->app->resolving('db', function($db)
+        {
             $db->extend('mongodb', function($config)
             {
                 return new Connection($config);