Dots in primitive names mess up generated table of contents

[nicolaspayette]

This is a problem for the view2.5d docs:

https://github.com/NetLogo/View2.5D/blob/update-documentation/README.md#primitives

The generated links are of the form:

[`view2.5d:patch-view`](#view2.5dpatch-view)

But the dot is stripped in actual GitHub anchors, so we should have this instead:

[`view2.5d:patch-view`](#view25dpatch-view)

[mrerrormessage]

I went through and removed : from the link name to appease github. I really don't know why strip . from anchors. Is there a definitive guide to which characters github will strip out of IDs? Mozilla's documentation indicates that . should be acceptable. I tried googling, but with little luck, do you have any ideas?

[nicolaspayette]

According to this comment, it strips everything but letters, numbers, spaces and hyphens (and turns spaces to hyphens). The comment also links to the source: https://github.com/jch/html-pipeline/blob/master/lib/html/pipeline/toc_filter.rb.