Subscriptions API CLI documentation

[cholmes]

Related Issue(s):

Closes #

Proposed Changes:

For inclusion in changelog (if applicable):

1. Added full documentation of subscriptions CLI

PR Checklist:

• This PR is as small and focused as possible
• If this PR includes proposed changes for inclusion in the changelog, the title of this PR summarizes those changes and is ready for inclusion in the Changelog.
• [] I have updated docstrings for function changes and docs in the 'docs' folder for user interface / behavior changes
• [] This PR does not break any examples or I have updated them

(Optional) @mentions for Notifications:

[cholmes]

@JuLeeAtPlanet - I think this has most everything documented for subscriptions. I didn't manage to fully test every command, so would definitely appreciate you going through and trying out everything I did, and ideally fully creating a subscription (like put in your auth stuff) to make sure it all works. Other feedback both big and small is also fully welcome - I made it pretty quickly in a spare couple of hours I had, so some stuff may be off.

[cholmes]

In merge caught that there was an extra space here.

[cholmes]

Note this section should change with #889 - just change the three places it says 'describe' with 'get' once that change is made.

[kevinlacaille]

FYI: PR #900 has been merged to main, which closed this ticket in reference.

[JuLeeAtPlanet]

@JuLeeAtPlanet - I think this has most everything documented for subscriptions. I didn't manage to fully test every command, so would definitely appreciate you going through and trying out everything I did, and ideally fully creating a subscription (like put in your auth stuff) to make sure it all works. Other feedback both big and small is also fully welcome - I made it pretty quickly in a spare couple of hours I had, so some stuff may be off.

Just read this more carefully, so I will go through and do a more detailed test of content before I finalize this second review.