aside Heading levels should not be checked for heading order with the main content

ACE 1.3.2

The [DAISY KB](https://kb.daisy.org/publishing/docs/html/asides.html) has identified an exception for `'s `that they don't have to follow the main content's heading level continuity.

> If a publisher cannot maintain heading numbering consistency, they should try to find another method that users can predict. For example, using h6 for all sidebars. In this case, though, the publisher should instruct users on this convention; for example, in a section on how to use the ebook.

I would suggest adding that information in the accessibilitySummary.

ACE should not flag headings which skip levels if they are found inside of an ``