Listing block default summary view uses headline html tags for its listing

[tiberiuichim]

Describe the bug

We should use a <ul> tag for the listing block, rather then the semantically-significant hx tags, as they can cause confusion in people relying on the page structure with headlines that function of section headers.

Another issue: in Plone classic the listing used to have significant colors, based on review state. It's useful, we should bring that back.

[davisagli]

We should use a

tag for the listing block

Agree -- but it's a breaking change.

Another issue

Please create another github issue then. It's unlikely that they will be fixed at the same time, and unlikely that someone who is working on one of them wants to follow the discussion of both in the same place.

[JeffersonBledsoe]

Just looking over #6318 which is linked to solve this. I agree on the use of the <ul> tag for the summary, however, I think being able to set a heading for the title of each element in the listing should be a function we retain. It's fairly common practise (e.g. see the search results page on the W3C website or the services and information section on the GOV.uk website) as the title and descriptive text are related. I see we already have a "Headline level" setting, could we add another option for "item heading level"? We could compute the item heading level from the headline level automatically (it should always be one below), but we may not always have a headline to actually compute this from