This reorganizes the file slightly to

- try to make it easier to find things (e.g., by not splitting up docs
  and code in completely separate sections)

- put the rule for docs/** higher, because the way it was before, it
  would have overwritten the more specific settings

- use rooted paths, to avoid accidentally matching subdirectories (e.g.,
  because there's a docs in dev_tools/ too)

I also removed a couple of users who either have left Google or have not
been involved for a long time.