Give users a way of suggesting changes to Cog-Book

[Shelton]

We need to give users a way of suggesting edits to any part of Cog-Book. Preferably, we link them to the exact Markdown file where they can then make the change and submit it. These will not commit to master, a PR will be created for us to review.

This process: https://help.github.com/articles/editing-files-in-another-user-s-repository/

To do:

• [x] Iterate on ways to give users the appropriate section link within context
• [x] Share with team
• [x] Roll out to each section

[Shelton]

@kevsmith researched how to use Sphinx as an alternative to ASCIIDoctor. A Sphinx build would help break the documentation down into separate pages that could then be PRed against.