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##### SUMMARY
<!--- Explain the problem briefly below, add suggestions to wording or structure -->
The [PSRP documentation](https://docs.ansible.com/ansible/latest/plugins/connection/psrp.html) mentions `ansible_psrp_connection_backoff` but this seems to be incorrect. The code appears to refer to `ansible_psrp_reconnection_backoff` instead (`reconnection` vs `connection`).
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##### 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 -->
PSRP
lib/ansible/plugins/connection/psrp.py

##### ANSIBLE VERSION
<!--- Paste verbatim output from "ansible --version" between quotes -->
```paste below
ansible 2.8.0.dev0
  config file = /etc/ansible/ansible.cfg
  configured module search path = [u'/root/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
  ansible python module location = /usr/local/lib/python2.7/dist-packages/ansible-2.8.0.dev0-py2.7.egg/ansible
  executable location = /usr/local/bin/ansible
  python version = 2.7.15rc1 (default, Nov 12 2018, 14:31:15) [GCC 7.3.0]
```

##### CONFIGURATION
<!--- Paste verbatim output from "ansible-config dump --only-changed" between quotes -->
```paste below
None
```

##### OS / ENVIRONMENT
<!--- Provide all relevant information below, e.g. OS version, browser, etc. -->
Linux, Ubuntu 18.04.2 LTS

##### ADDITIONAL INFORMATION
<!--- Describe how this improves the documentation, e.g. before/after situation or screenshots -->
None.
<!--- HINT: You can paste gist.github.com links for larger files -->
- name: ansible_psrp_negotiate_delegate
  negotiate_hostname_override:
    description:
    - Override the remote hostname when searching for the host in the Kerberos
      lookup.
    - This allows Ansible to connect over IP but authenticate with the remote
      server using it's DNS name.
    - Only valid when Kerberos was the negotiated auth or was explicitly set as
      the authentication.
    - Ignored when NTLM was the negotiated auth.
    vars:
    - name: ansible_psrp_negotiate_hostname_override
  negotiate_send_cbt:
    description:
    - Send the Channel Binding Token (CBT) structure when authenticating.
    - CBT is used to provide extra protection against Man in the Middle C(MitM)
      attacks by binding the outer transport channel to the auth channel.
    - CBT is not used when using just C(HTTP), only C(HTTPS).
    default: yes
    type: bool
    vars:
    - name: ansible_psrp_negotiate_send_cbt
  negotiate_service:
    description:
    - Override the service part of the SPN used during Kerberos authentication.
    - Only valid when Kerberos was the negotiated auth or was explicitly set as
      the authentication.
    - Ignored when NTLM was the negotiated auth.
    default: WSMAN
    vars: