When using --json, if the command raises an unexpected exception, we

end up showing an empty "success" payload. This is clearly not what we

want. This change insteads records an "Internal Error"  with the

exception's error message, allowing tools to know that something went

wrong.
The help string for --json has also been updated to include a trailing

period, matching other help strings. It also now includes an added_in

version for the documentation, and the Version Added for JSONOutput

now correctly shows 3.0.

Tested --json with an exception raised, and saw the exception details.
Saw the corrected help text.