Remove 'response_class' from getresponse docstring.
This variable is not documented as part of the API in the standard
library documentation; it should be considered as an implementation
detail and as such should not be included in the doc string.
Closes #57665.
"""Get the response from the server.
If the HTTPConnection is in the correct state, returns an
- instance of HTTPResponse or of whatever object is returned by
- the response_class variable.
+ instance of HTTPResponse.
If a request has not been sent or if a previous response has
not be handled, ResponseNotReady is raised. If the HTTP