Python3 syntax compatibility for modules

docsite/rst/developing_modules.rst

@@ -634,6 +634,7 @@ The following  checklist items are important guidelines for people who want to c
 
 * The shebang should always be ``#!/usr/bin/python``, this allows ansible_python_interpreter to work
 * Modules must be written to support Python 2.4. If this is not possible, required minimum python version and rationale should be explained in the requirements section in DOCUMENTATION.
+* Modules must be written to use proper Python-3 syntax.  At some point in the future we'll come up with rules for running on Python-3 but we're not there yet.  See :doc:`developing_modules_python3` for help on how to do this.
 * Documentation: Make sure it exists
     * Module documentation should briefly and accurately define what each module and option does, and how it works with others in the underlying system. Documentation should be written for broad audience--readable both by experts and non-experts. This documentation is not meant to teach a total novice, but it also should not be reserved for the Illuminati (hard balance).
     * If an argument takes both C(True)/C(False) and C(Yes)/C(No), the documentation should use C(True) and C(False).