Also remove the bool casting function info (transparent to module writer now)

docsite/rst/developing_modules.rst

@@ -335,7 +335,7 @@ and guidelines:
 
 * If you have a company module that returns facts specific to your installations, a good name for this module is `site_facts`.
 
-* Modules accepting boolean status should generally accept 'yes', 'no', 'true', 'false', or anything else a user may likely throw at them.  The AnsibleModule common code supports this with "type='bool'" and a module.boolean(value) casting function.
+* Modules accepting boolean status should generally accept 'yes', 'no', 'true', 'false', or anything else a user may likely throw at them.  The AnsibleModule common code supports this with "type='bool'".
 
 * Include a minimum of dependencies if possible.  If there are dependencies, document them at the top of the module file, and have the module raise JSON error messages when the import fails.