Prompt for additional metadata during issue/pr create - #839

This is ready to be taken for a spin! To test this out:

1. bin/gh issue create -R <OWNER/REPO>
2. bin/gh pr create -R <OWNER/REPO>

Tips:

• Choose a repo in a large organization to get a feel of how multiple selects work for many assignees/reviewers;
• For testing, as long as you always choose "Cancel" in the end instead of "Submit" no branch will be published nor any data submitted.

My observations:

• In my testing, I found it confusing that multi-select items are chosen with Space, while single-select lists are chosen with Enter. If users accidentally press the wrong key to confirm their selection and move on, they might get confused by unexpected results; in multi-select, Enter will move on to the next prompt even if no item was selected, and in single-select (e.g. milestone picker) Space will enter filtering mode and Backspace will be needed to recover from that. These key interactions are defined by the defaults of the Survey library for terminal prompts.
• For a large org such as github, choosing to select assignees/reviewers/projects results in a large (~10s) delay with no visual feedback. I suggest that we display the loading spinner in the meantime to avoid having the command feel like it's "stuck"

/cc @ampinsk

I agree with those observations. I found it confusing at first, but eventually got used to it. I still wished there was a way to go back and edit but I suppose the user can select Continue in Browser and make the edits as needed.

• I believe I spotted a bug when there is no Project set by the repo admin. It returned this and then ended the gh pr create abruptly without saving any of my selections:

  could not collect title and/or body: could not prompt: please provide options to select from

• Also, when the user opts to add metadeta, but then hits enter right away, we still show the "What would you like to add?" text but with no result after it. Not a big deal, but wanted to point it out. I guess no answer means "nothing" 🤷

• I believe I spotted a bug when there is no Project set by the repo admin. It returned this and then ended the gh pr create abruptly without saving any of my selections:

@tierninho Nice find!

Overall I think this is looking awesome!

In my testing, I found it confusing that multi-select items are chosen with Space, while single-select lists are chosen with Enter. If users accidentally press the wrong key to confirm their selection and move on, they might get confused by unexpected results; in multi-select, Enter will move on to the next prompt even if no item was selected, and in single-select (e.g. milestone picker) Space will enter filtering mode and Backspace will be needed to recover from that. These key interactions are defined by the defaults of the Survey library for terminal prompts.

Agreed this is a little awkward but I think under the circumstances and once you're used to it it's not too bad. Maybe we can update the instructions [Use arrows to move, space to select, type to filter] to include Enter to continue? That's getting long but maybe we could replace Use arrows to move since that one feels more obvious? Happy to leave this as an enhancement later and know we're probably constrained by the library here.

For a large org such as github, choosing to select assignees/reviewers/projects results in a large (~10s) delay with no visual feedback. I suggest that we display the loading spinner in the meantime to avoid having the command feel like it's "stuck"

+1 on using a spinner for these long waits!