suggested updates for documenting all cameras

[sbailey]

Rather than try to describe in English my suggested changes to branch spectrograph-tests before merging PR #73, here is a PR to that branch with suggested changes to document all cameras. I recognize that this might cause the validator to generate a bunch of warnings about missing HDUs, but ok.

[weaverba137]

Looks fine to me. Are you going to comment on the per-keyword problems I noted? And other stuff in the Problems section?

as long as it doesn't outright crash from me getting the doc syntax wrong.

Well, looks like it's crashing because the doc syntax is wrong. Just a minor table formatting problem.

[sbailey]

I fixed the table whitespace problem.

Let's address the other per-keyword problems in separate discussions, and leave those notes in this PR as is and merge. i.e. they aren't issues with the datamodel documentation itself, but rather issues with what we want the data format to be, which requires iterations and code updates with Klaus.