Fix documentation inconsistency on version specifier
Fix documentation inconsistency on version specifier

The `,` is the equivalent of an "and".
Also, the pkg_resources section documents and behave like this too:

```
>>> pkg_resources.Requirement('requests>1,>2').specifier.contains('1.2.3')
False
>>> pkg_resources.Requirement('requests>1,>2').specifier.contains('2.3.4')
True
```

pypa/setuptools,pypa/setuptools,pypa/setuptools