Documentation
There are two versions of the documentation:
Documentation 2: https://doc.tmpe.me created from GitHub Wiki data files using Jetbrains Writerside
Documentation 1: https://github.com/krzychu124/Cities-Skylines-Traffic-Manager-President-Edition/wiki
Old (website is down, see Wayback Machine internet archive): https://tmpe.viathinksoft.com/wiki/
Contributing to Documentation 2 (doc.tmpe.me)
Apply the ordinary GitHub contribution flow (fork, branch, create pull request) to https://github.com/CitiesSkylinesMods/DocumentationWiki
Use British English with Oxford spelling for -ise/-ize words
Using Jetbrains Writerside really helps, but you don't have to, it's all Markdown!
Fate of Other Documentation Versions
Old documentation is good as gone, the website is down. You can access it using Wayback Machine internet archive. Documentation 1 is still available on GitHub.