The documentation of strip() / lstrip() / rstrip() should define "whitespace" more precisely.

The Python 3 documentation refers to "ASCII whitespace" for bytes.strip() / bytes.lstrip() / bytes.rstrip() and "whitespace" for str.strip() / str.lstrip() / str.rstrip(). I suggest the following improvements:
* add a link from "ASCII whitespace" to string.whitespace or bytes.isspace(),
* define plain "whitespace" more precisely (possibly with a link to str.isspace()).

The Python 2 documentation refers to plain "whitespace". As far as I know strip() removes ASCII whitespaces only. If so, please:
* add a link to string.whitespace or str.isspace(),
* improve the string.whitespace documentation and explain that it is locale-dependent (see documentation of str.isspace()).