bpo-34848 : Correct a method signature in docstring for range(..).index method

[srinivasreddy]

https://bugs.python.org/issue34848

[srinivasreddy]

>>> range(100).index(2,0,10)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: index() takes exactly one argument (3 given)
>>> range(100).index(2,0)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: index() takes exactly one argument (2 given)
>>> range(100).index(2)
2
>>> range(100).index(100)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: 100 is not in range
>>> range(100).index(99)
99

[miss-islington]

Thanks @srinivasreddy for the PR, and @vstinner for merging it 🌮🎉.. I'm working now to backport this PR to: 3.7.
🐍🍒⛏🤖

[bedevere-bot]

GH-13075 is a backport of this pull request to the 3.7 branch.