Some links seems to be broken on the CONTRIBUTING.md, the wiki folder doesn't exists anymore. If you want me to fix it just gently asign to me.

https://github.com/chaijs/chai/blob/4.x.x/CONTRIBUTING.md
For example, the coding style guidelines link is broken:
coding style guidelines