<!--- 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 [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 -->
from ansible.errors import AnsibleConnectionFailure, AnsibleError
from ansible.errors import AnsibleFileNotFound
from ansible.module_utils.parsing.convert_bool import boolean
from ansible.module_utils._text import to_bytes, to_native, to_text
from ansible.plugins.connection import ConnectionBase
from ansible.plugins.shell.powershell import _common_args
from ansible.utils.display import Display
from ansible.utils.hashing import secure_hash
HAS_PYPSRP = True
PYPSRP_IMP_ERR = None
try:
    import pypsrp
    from pypsrp.complex_objects import GenericComplexObject, PSInvocationState, RunspacePoolState
    from pypsrp.exceptions import AuthenticationError, WinRMError
    from pypsrp.host import PSHost, PSHostUserInterface
    from pypsrp.powershell import PowerShell, RunspacePool
    from pypsrp.shell import Process, SignalCode, WinRS
    from pypsrp.wsman import WSMan, AUTH_KWARGS
    from requests.exceptions import ConnectionError, ConnectTimeout
except ImportError as err:
    HAS_PYPSRP = False
    PYPSRP_IMP_ERR = err
display = Display()
class Connection(ConnectionBase):
    transport = 'psrp'
    module_implementation_preferences = ('.ps1', '.exe', '')
    allow_executable = False
    has_pipelining = True
    allow_extras = True
    def __init__(self, *args, **kwargs):