Issue title: junos_facts: gather_network_resources has wrong/misleading documentation
 Issue body: <!--- Verify first that your improvement is not already reported on GitHub -->
<!--- Also test if the latest release and devel branch are affected too -->
<!--- Complete *all* sections as described, this form is processed automatically -->

##### SUMMARY
<!--- Explain the problem briefly below, add suggestions to wording or structure -->
The `gather_network_resources`of `junos_facts` has its documentation copied from the `gather_subset` option. It is unclear what the difference between these two options is or what `gather_network_resources` does.
<!--- HINT: Did you know the documentation has an "Edit on GitHub" link on every page ? -->

##### ISSUE TYPE
- Documentation Report

##### COMPONENT NAME
<!--- Write the short name of the rst file, module, plugin, task or feature below, use your best guess if unsure -->
junos_facts

##### ANSIBLE VERSION
<!--- Paste verbatim output from "ansible --version" between quotes -->
```paste below
ansible 2.9.6
  config file = /XXX/ansible.cfg
  configured module search path = ['/home/net/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /home/net/.local/lib/python3.7/site-packages/ansible
  executable location = /home/net/.local/bin/ansible
  python version = 3.7.3 (default, Dec 20 2019, 18:57:59) [GCC 8.3.0]
```

 Comments: 
 Comment 0: Files identified in the description:
* [`lib/ansible/modules/network/junos/junos_facts.py`](https://github.com/ansible/ansible/blob/devel/lib/ansible/modules/network/junos/junos_facts.py)

If these files are incorrect, please update the `component name` section of the description or use the `!component` bot command.

[click here for bot help](https://github.com/ansible/ansibullbot/blob/master/ISSUE_HELP.md)
<!--- boilerplate: components_banner --->
 Comment 1: @sebastianw, just so you are aware we have a dedicated Working Group for network.
You can find other people interested in this in `#ansible-network` on Freenode IRC
For more information about communities, meetings and agendas see https://github.com/ansible/community

[click here for bot help](https://github.com/ansible/ansibullbot/blob/master/ISSUE_HELP.md)
<!--- boilerplate: community_workgroups --->
 Comment 2: Thank you very much for your interest in Ansible. This plugin is no longer maintained in this repository and has been migrated to https://github.com/ansible-collections/junipernetworks.junos

Please re-submit this issue in the above repository.

If you have further questions please stop by IRC or the mailing list:

   * IRC: #ansible on irc.freenode.net
   * mailing list: https://groups.google.com/forum/#!forum/ansible-project
{'source': 'GithubIssues', 'repo_name_with_owner': 'ansible/ansible', 'issue_id': 595751878, 'repo_stars': 55309.0}