Update README.md

Author: chrisjsewell

README.md

@@ -9,6 +9,7 @@ It is still under development, so should be used with caution.
 Details of the port can be found in `markdown_it/port.yaml` and in `port.yaml`
 within the extension folders. But the driving design philosiphy has been to change as little of the
 fundamental code structure (file names, function name, etc) as possible.
+It is very simple to write complimentary extensions for both language implementations!
 
 Basic usage: