Add api_info and api_modify modules (#91)

* Add api_info and api_modify modules.

* Add documentation, and cross-references for the modules.

* Bump version added for new modules.

* Ignore dynamic entries. Allow _info module to return them.

* Document behavior for dynamic entries.

* Update license headers.

* Add disclaimer.

* Improve formulation.

* Auto-generate path list in DOCUMENTATION.

* Add test to make sure lists have been generated automatically.

tests/sanity/extra/update-docs.py

@@ -0,0 +1,22 @@
+#!/usr/bin/env python
+# Copyright (c) Ansible Project
+# GNU General Public License v3.0+ (see LICENSES/GPL-3.0-or-later.txt or https://www.gnu.org/licenses/gpl-3.0.txt)
+# SPDX-License-Identifier: GPL-3.0-or-later
+"""Check whether update-docs.py modifies something."""
+from __future__ import (absolute_import, division, print_function)
+__metaclass__ = type
+
+import os
+import sys
+import subprocess
+
+
+def main():
+    """Main entry point."""
+    p = subprocess.run(['./update-docs.py'], check=False)
+    if p.returncode not in (0, 1):
+        print('{0}:0:0: unexpected return code {1}'.format(sys.argv[0], p.returncode))
+
+
+if __name__ == '__main__':
+    main()