fix: Remove multiple EOL when creating route or middleware (#790)

Co-authored-by: Renan <[email protected]>

Author: jsgalarraga

bricks/dart_frog_new/__brick__/{{~ middleware.dart }}

@@ -1,4 +1,4 @@
 Handler middleware(Handler handler) {
   // TODO: implement middleware
   return handler;
-}
+}

bricks/dart_frog_new/__brick__/{{~ route.dart }}

@@ -5,4 +5,4 @@
 ) {
 {{/params.0}}  // TODO: implement route handler
   return Response(body: 'This is a new route!');
-}
+}