Change ambiguous description of backoff_factor (#1436)
Change ambiguous description of backoff_factor (#1436)

Change from `^` to `**`. Programmers not familiar with python might assume the ^ is the exponent operator, when in fact it is the bitwise XOR operator. This change will remove the ambiguity.
sigmavirus24/urllib3,urllib3/urllib3,urllib3/urllib3,sigmavirus24/urllib3