Docs: unspecified unsigned int type requirement

[PurpleSensation]

Hi, I just spent a full morning to find out that the function point_in_poly() requires unsigned values as input. I might learn a bit about GitHub and suggest additions to the Docs. I've been working with the python bindings for a year and the documentation needs some polish.

[teseoch]

The doc comes directly from the comments in the C++ version

to make changes in git, fork the repo (there is a button), create a branch make your change and push. On github a new button with pull request will appear, make the pull request and it will appear here if good, I can then merge it to the main code