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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`).
<!--- 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 -->
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 -->
supported_args.extend(auth_kwarg)
        extra_args = set([v.replace('ansible_psrp_', '') for v in
                          self.get_option('_extras')])
        unsupported_args = extra_args.difference(supported_args)
        for arg in unsupported_args:
            display.warning("ansible_psrp_%s is unsupported by the current "
                            "psrp version installed" % arg)
        self._psrp_conn_kwargs = dict(
            server=self._psrp_host, port=self._psrp_port,
            username=self._psrp_user, password=self._psrp_pass,
            ssl=self._psrp_protocol == 'https', path=self._psrp_path,
            auth=self._psrp_auth, cert_validation=self._psrp_cert_validation,
            connection_timeout=self._psrp_connection_timeout,
            encryption=self._psrp_message_encryption, proxy=self._psrp_proxy,
            no_proxy=self._psrp_ignore_proxy,
            max_envelope_size=self._psrp_max_envelope_size,
            operation_timeout=self._psrp_operation_timeout,
            certificate_key_pem=self._psrp_certificate_key_pem,
            certificate_pem=self._psrp_certificate_pem,
            credssp_auth_mechanism=self._psrp_credssp_auth_mechanism,
            credssp_disable_tlsv1_2=self._psrp_credssp_disable_tlsv1_2,
            credssp_minimum_version=self._psrp_credssp_minimum_version,
            negotiate_send_cbt=self._psrp_negotiate_send_cbt,
            negotiate_delegate=self._psrp_negotiate_delegate,
            negotiate_hostname_override=self._psrp_negotiate_hostname_override,
            negotiate_service=self._psrp_negotiate_service,
        )
        
        if hasattr(pypsrp, 'FEATURES') and 'wsman_read_timeout' in pypsrp.FEATURES:
            self._psrp_conn_kwargs['read_timeout'] = self._psrp_read_timeout