`itertools.rst` says that `start` is a required argument for `count`, while it is not

[sobolevn]

Bug report

However,

>>> import itertools
>>> itertools.count()
count(0)
>>> next(itertools.count())
0

I propose that we use [start, step] instead.

Linked PRs

• gh-111343: Fix itertools docs: start arg is optional for count #111344
• [3.12] gh-111343: Fix itertools docs: start arg is optional for count (gh-111344) #111385

[zware]

Ideally we'd use the more accurate start=0, step=1, but I'm not sure that really fits the format of the table.

[sobolevn]

[start, step] might also look like a list with two items for some users 🤔

[zware]

[start[, step]] implies that step can only be specified in conjunction with start, which also isn't true.