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<!--- 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 [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 -->
host=self._psrp_host)
                    b64_data = base64.b64encode(data) + b"\r\n"
                    process.send(b64_data, end=(src_file.tell() == in_size))
                
                if offset == 0:
                    process.send(b"", end=True)
            process.end_invoke()
            process.signal(SignalCode.CTRL_C)
        if process.rc != 0:
            raise AnsibleError(to_native(process.stderr))
        put_output = json.loads(process.stdout)
        remote_sha1 = put_output.get("sha1")
        if not remote_sha1:
            raise AnsibleError("Remote sha1 was not returned, stdout: '%s', "
                               "stderr: '%s'" % (to_native(process.stdout),
                                                 to_native(process.stderr)))
        local_sha1 = secure_hash(in_path)
        if not remote_sha1 == local_sha1:
            raise AnsibleError("Remote sha1 hash %s does not match local hash "
                               "%s" % (to_native(remote_sha1),
                                       to_native(local_sha1)))
    def fetch_file(self, in_path, out_path):
        super(Connection, self).fetch_file(in_path, out_path)
        display.vvv("FETCH %s TO %s" % (in_path, out_path),
                    host=self._psrp_host)
        in_path = self._shell._unquote(in_path)
        out_path = out_path.replace('\\', '/')
        
        
        max_b64_size = int(self.runspace.connection.max_payload_size -