Add documentation for module option context (#1057)

* Add documentation for module option context

* suggestion

Co-authored-by: Don Naro <dnaro@redhat.com>

* Expand docs to indicate context is not used by core

---------

Co-authored-by: Don Naro <dnaro@redhat.com>

Author: sivel

docs/docsite/rst/dev_guide/developing_program_flow_modules.rst

@@ -766,6 +766,23 @@ This section will discuss the behavioral attributes for arguments:
 
   If ``options`` is specified, ``required_by`` refers to the sub-options described in ``options`` and behaves as in :ref:`argument_spec_dependencies`.
 
+:context:
+
+  .. versionadded:: 2.17
+
+  You can set the value of the ``context`` key to a dict of custom content. This allows you to provide additional context in the argument spec. The content provided is not validated or utilized by the core engine.
+
+  Example:
+
+  .. code-block:: python
+
+      option = {
+          'type': 'str',
+          'context': {
+              'disposition': '/properties/apiType',
+          },
+          'choices': ['http', 'soap'],
+      }
 
 .. _argument_spec_dependencies: