Added blank line between selectors in jumbotron

less/jumbotron.less

@@ -13,6 +13,7 @@
   .h1 {
     color: @jumbotron-heading-color;
   }
+  
   p {
     margin-bottom: (@jumbotron-padding / 2);
     font-size: @jumbotron-font-size;