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/dnstxt.py

@@ -1,22 +1,48 @@
 # (c) 2012, Jan-Piet Mens <jpmens(at)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: dnstxt
+    author: Jan-Piet Mens (@jpmens) <jpmens(at)gmail.com>
+    version_added: "0.9"
+    short_description: query a domain(s)'s DNS txt fields
+    requirements:
+      - dns/dns.resolver (python library)
+    description:
+      - Uses a python library to return the DNS TXT record for a domain.
+    options:
+      _terms:
+        description: domain or list of domains to query TXT records from
+        required: True
+        type: list
+"""
+
+EXAMPLES = """
+- name: show txt entry
+  debug: msg="{{lookup('dnstxt', ['test.example.com'])}}"
+
+- name: iterate over txt entries
+  debug: msg="{{item}}"
+  with_dnstxt:
+    - 'test.example.com'
+    - 'other.example.com'
+    - 'last.example.com'
+
+- name: iterate of a comma delimited DNS TXT entry
+  debug: msg="{{item}}"
+  with_dnstxt: "{{lookup('dnstxt', ['test.example.com']).split(',')}}"
+"""
+
+RETURN = """
+  _list:
+    description:
+      - values returned by the DNS TXT record.
+    type: list
+"""
+
 HAVE_DNS = False
 try:
     import dns.resolver
@@ -29,7 +55,6 @@ from ansible.errors import AnsibleError
 from ansible.module_utils._text import to_native
 from ansible.plugins.lookup import LookupBase
 
-
 # ==============================================================
 # DNSTXT: DNS TXT records
 #
@@ -37,6 +62,7 @@ from ansible.plugins.lookup import LookupBase
 # TODO: configurable resolver IPs
 # --------------------------------------------------------------
 
+
 class LookupModule(LookupBase):
 
     def run(self, terms, variables=None, **kwargs):