feat(docs): Add Improve this doc link in each doc page, which links to t...

Added a "Improve this doc" button to each page in the generated documentation. The button links to Github for the file containing the doc, in Edit mode.

Also had to remove a done() call from gen-docs.js, because it wasn't working. Not sure if this was broken or something specific to my machine.

Please try this out before merging it in.