It's neither "bug" nor "feature" - it's an inherited quirk CPython maintains to avoid annoying users for no good reason.

If you absolutely have to "do something", how about adding a mere footnote?  The docs already imply the args have the same restrictions as for `range()`.  A footnote could add that, to preserve historical compatibility, CPython also accepts arguments `x` for which `int(x) == x`, and uses `int(x)` in such cases - but portable code shouldn't rely on that.

But nobody cares, so putting that in the main part of the docs would also annoy 99.99% of users for no good reason ;-)