edit (especially summary and description) should use a line editor

[allanwind]

The current workflow is to either discard the original content and write what you want, or to copy and paste the text with your mouse so you can edit it. It would be a more friendly workflow to present the default value and allow the user to modify the default value (if set) like gnu readline (python readline seems to be something else). It would eliminate the magic "None" values currently used to differentiate between accept default value opposed to unset it. The edit command seems to straddle the cliff between the interactive mode and not being able to make changes non-interactively via options and arguments.