Document how to exclude pages/posts from search index

ref #1369

docs/_docs/10-layouts.md

@@ -7,7 +7,7 @@ single_layout_gallery:
     alt: "single layout with header example"
   - image_path: /assets/images/mm-layout-single-meta.png
     alt: "single layout with comments and related posts"
-last_modified_at: 2017-11-15T15:01:40-05:00
+last_modified_at: 2017-11-28T08:42:54-05:00
 toc: true
 toc_label: "Included Layouts"
 toc_icon: "columns"
@@ -275,6 +275,14 @@ A page with a search form. Add `layout: search` to the YAML Front Matter similar
 
 ![search page layout example]({{ "/assets/images/search-layout-example.png" | absolute_url }})
 
+### Exclusions
+
+If you would like to exclude specific pages/posts from the search index set the search flag to `false` in the YAML Front Matter for the page/post.
+
+```yaml
+search: false
+```
+
 **ProTip:** Add a link to this page in the masthead navigation.
 {: .notice--info}