There are two points to this ticket:

1. The GridFS docs for the ruby driver currently recommend using #find_one to query a file and return its contents in one step. This method has been deprecated since 2016, however. We need to update the docs to reflect the current best practice (a two-step process with #find, followed by one of the download methods).
2. Related to that, it would be nice to have a convenience method that we can use to replace #find_one, since being able to grab the file contents directly would be pretty nice. In which case, the docs could be updated to include both the current best practice, and to mention this convenience helper method.