README.md in jekyll_flexible_include-2.0.18 vs README.md in jekyll_flexible_include-2.0.19

@@ -77,9 +77,10 @@
 Note that the [square brackets] merely indicate optional parameters
 and are not intended to be written literally.
 
 
 ### Options
+  * `attribution` see [`jekyll_plugin_support`](https://github.com/mslinn/jekyll_plugin_support#subclass-attribution)
   * `do_not_escape` keyword option caused the content to be included without HTML escaping it.
     By default, the included file will escape characters <code>&lt;</code>,
     <code>{</code> and <code>}</code> unless the <code>do_not_escape</code> keyword option is specified.
 
   * `highlight='regex pattern here'` wraps content matching the regex pattern within a