[Documentation] stroke and strokeWidth

Also found a tiny documentation bug.

stroke says, it is used to outline the shapes drawn with ellipse() and rect(). But it is also used for the color of the line() function. Same applies to strokeWidth().

It’s mentioned in the description of the line() function itself, but should probably also be put into stroke and strokeWidth.

Thanks for reporting this glsooogls – would you be able to open an issue for it on the tracker? https://bitbucket.org/TwoLivesLeft/codea/issues