We want to make the slim_header.html as the basis for the modern header
template that will be used everywhere, eventually replacing header.html.
Rather than making the page explorer be the special case where we want
the last item to be bigger, do it the other way around i.e. use the
smaller font size on the create/edit views. This ensures that the big
font size is used on all other views e.g. Inspect view.
Remove use of shared/filters.html, as it contains a duplicate `<form>` element we don't want, and generally has more stuff we don't want than stuff we do, to the point that it'll just get in the way of restyling.
Where possible, adopt a subset of stylelint-config-wagtail changes.
- Formatting & ordering (auto applied), this includes the padding/inset shorthand changes
- Adopt a small set of no-union-classes changes as an example of changes to come in future PRs
- Ignore some areas where we are selecting against data* attributes that will not be practical to change
- Move some no-important ignore rules to specific lines
- Ignore max-combinators in modeladmin styles (legacy)
- Remove error messages forced-color-adjust setting to none
- Ensure that some rules are always ignored in overrides (aka vendor) styles. This avoids us having to add ignore comments all over these styles.
- Resolves #10719
At this point wagtailadmin/shared/field.html is still used by FieldPanel, as well as third-party code. Replace this by a template that simply pulls the relevant context variables from the template and passes them on to `{% formattedfield %}` (which renders them using the old template, now renamed formatted_field.html). This will allow us to move logic from the template to the tag function without breaking the existing wagtailadmin/shared/field.html API.
- Set the side panel width custom property ('--side-panel-width') globally, not just on the form container.
- Use this custom property to determine the max width of the form content.
- Fixes #11038
Ensures that when the iframe content is loaded there is a background on the iframe. So that transparent websites show correctly in the preview panel.
Fixes #11174
These will not be removed in 6.0, to ensure that the two-release deprecation period is still in place.
The removal of the legacy moderation is an exception, as this was slated for removal from 2.x, long before the deprecation warnings were put in place.
