Improve build speed for large sites by avoiding a document find on ev…

…ery page (breaking change for those styling custom pages with body classes)

_includes/body_classes.html

@@ -11,9 +11,6 @@
 {%- assign componenturl = '/' -%}
 {%- for part in path_parts -%}
   {%- assign componenturl = componenturl | append: part | append: '/' -%}
-  {%- assign componentpage = site.documents | find: 'url', componenturl -%}
-  {%- if componentpage and componentpage.title %}
-    page-{{ componentpage.title | slugify }}
-  {% endif -%}
-{%- endfor %}
-ispage-{{ page.title | slugify }}
+  page-{{ componenturl | slugify }}
+{% endfor %}
+ispage-{{ page.url | slugify }}