TOC: Missing titles and title inconsistency

Problem/Motivation

I think the way the "on this page" titles works, out of the box it is looking for H2s. A number of components are missing the ability to add titles and they are not able to be captured in "on this page".

• Accordion
• Slider
• Content
• iframe
• webform
• Callout
• map
• next step

There is also other inconsistencies. One this page links to slides in the slider but not the slider title. I realise that this can be overridden in the theming, but this is a very weird UX by defaultl Slides are generally secondary content and the key items for a page.

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes