Editorial fixes

[nigelmegitt]

• [ ] Remove DFXP Editorial note
• [ ] Remove trailing ) from Acknowledgements heading
• [ ] Move authors to Acknowledgements section
• [ ] Change EXAMPLE 1 in §7.5 to use class="example" correctly.
• [ ] Check for duplicate id values

[nigelmegitt]

Closing since work on ADPT has moved to DAPT. I don't expect to address these.