Small UI improvement to snippet form

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/assets/stylesheets/sections/snippets.scss

-.snippet.file-holder {
-  .file-title {
-    .snippet-file-name {
-      padding: 4px 10px;
-      position: relative;
-      top: -4px;
-      left: -4px;
-    }
-  }
-}
-
 .my-snippets li:first-child {
   h4 { margin-top: 0; }
   padding-top: 0;

app/views/projects/snippets/_form.html.haml

@@ -18,7 +18,7 @@
         .col-sm-10
           .file-holder.snippet
             .file-title
-              = f.text_field :file_name, placeholder: "example.rb", class: 'snippet-file-name', required: true
+              = f.text_field :file_name, placeholder: "example.rb", class: 'form-control snippet-file-name', required: true
             .file-content.code
               %pre#editor= @snippet.content
               = f.hidden_field :content, class: 'snippet-file-content'