Add <pre> styles and fix check out branch modal

app/assets/stylesheets/framework/typography.scss

@@ -321,6 +321,16 @@ h6 {
 /** CODE **/
 pre {
   font-family: $monospace_font;
+  display: block;
+  padding: $gl-padding-8;
+  margin: 0 0 $gl-padding-8;
+  font-size: 13px;
+  word-break: break-all;
+  word-wrap: break-word;
+  color: $gl-text-color;
+  background-color: $gray-light;
+  border: 1px solid $border-color;
+  border-radius: $border-radius-small;
 }
 
 code {

app/views/projects/merge_requests/_how_to_merge.html.haml

@@ -2,8 +2,8 @@
   .modal-dialog
     .modal-content
       .modal-header
-        %a.close{ href: "#", "data-dismiss" => "modal" } ×
         %h3 Check out, review, and merge locally
+        %a.close{ href: "#", "data-dismiss" => "modal" } ×
       .modal-body
         %p
           %strong Step 1.