GH-98363: Add itertools.batched()

[rhettinger]

• Issue: Add itertools.batched() #98363

[JelleZijlstra]

I agree with adding this, just a few small comments.

[bedevere-bot]

🤖 New build scheduled with the buildbot fleet by @rhettinger for commit b9cbb46 🤖

If you want to schedule another build, you need to add the ":hammer: test-with-buildbots" label again.

[gvanrossum]

Maybe tweak the example so it cannot be misunderstood as "return 3 batches"?

[anderssonjohan]

Suggested change

	# batched('ABCDEFG', 3) --> ABC DEF G
	# list(batched('ABCDEFG', 3)) --> [['A', 'B', 'C'], ['D', 'E', 'F'], ['G']]