Clean up "HTTP Parameters" view a bit for EditEngine forms

Summary: Ref T10004. This lost a couple of fields when I rearranged how descriptions work. Restore them.

Test Plan:

• Viewed "Using HTTP Parameters".
• Everything had nice descriptions.
• No more weird phantom/misleading 'comment' transaction in UI.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T10004

Differential Revision: https://secure.phabricator.com/D14822