Lookup docs (#30280)

* finalize lookup documentation
* minor fixes to ansible-doc
 - actually show which file caused error on when listing plugins
 - removed redundant display of type and name
* smart quote fixes from toshio

lib/ansible/plugins/lookup/nested.py

@@ -1,22 +1,52 @@
 # (c) 2012, Michael DeHaan <michael.dehaan@gmail.com>
-#
-# This file is part of Ansible
-#
-# Ansible is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# Ansible is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with Ansible.  If not, see <http://www.gnu.org/licenses/>.
+# (c) 2017 Ansible Project
+# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
 from __future__ import (absolute_import, division, print_function)
 __metaclass__ = type
 
+DOCUMENTATION = """
+    lookup: nested
+    version_added: "1.1"
+    short_description: composes a list with nested elements of other lists
+    description:
+        - Takes the input lists and returns a list with elements that are lists composed of the elements of the input lists
+    options:
+      _raw:
+         description:
+           - a set of lists
+         required: True
+"""
+
+EXAMPLES = """
+- name: give users access to multiple databases
+  mysql_user:
+    name: "{{ item[0] }}"
+    priv: "{{ item[1] }}.*:ALL"
+    append_privs: yes
+    password: "foo"
+  with_nested:
+    - [ 'alice', 'bob' ]
+    - [ 'clientdb', 'employeedb', 'providerdb' ]
+As with the case of 'with_items' above, you can use previously defined variables.:
+
+- name: here, 'users' contains the above list of employees
+  mysql_user:
+    name: "{{ item[0] }}"
+    priv: "{{ item[1] }}.*:ALL"
+    append_privs: yes
+    password: "foo"
+  with_nested:
+    - "{{ users }}"
+    - [ 'clientdb', 'employeedb', 'providerdb' ]
+"""
+
+RETURN = """
+  _list:
+    description:
+      - A list composed of lists paring the elements of the input lists
+    type: list
+"""
+
 from jinja2.exceptions import UndefinedError
 
 from ansible.errors import AnsibleError, AnsibleUndefinedVariable