:mrjob-opt:`some_value`

Wheeee!

While writing this, I discovered a problem with the build process. (btw, readthedocs is currently failing builds due to the missing `PYTHONPATH` tweak.)

I thought the order of operations was:

1. Read all the documents in
2. Call `doctree-read`
3. Resolve all the references
4. Call `doctree-resolved`

But it's actually

1. Read a document
2. Call `doctree-read` for that document
3. Go to 1 unless no documents left
4. Call `doctree-resolved`

which is a major issue, because it means the option lists are getting populated before all the options have been scanned. Not sure how to fix that one yet, but it must have a solution. Probably wait to merge this until I figure it out, otherwise our readthedocs builds will start succeeding again and the online reference will be incomplete.