The best way to contribute to the documentation is to follow an issue-based workflow.
Ways to contribute
Triage: Review open issues. You can confirm that the issue is still valid, or no longer valid.
Open New Issues: Have you run into trouble finding something in the docs, or found that the instructions provided no longer work? Or know of a page in the documentation that you're familiar with? Review it for accuracy and ease of reading, and open an issue for making it better.
Found an issue that you can address? Follow the typical github workflow: fork, branch, write, commit, push, and open a pull request!
checked the original page referenced in the issue and found that it'd been rewritten since I last looked, and that instructions for installing developer tools had been moved.
checked the new page(s) referenced by the previous step and verified that they now include OS-specific details.