The value of a `style` attribute is a list of CSS declarations, but it
was printed exactly as written, so whatever spacing it was pasted with
stayed. It now goes through the CSS formatter, the way a `<style>`
element already did.

An attribute is not a block: the declarations stay on the tag's line
while they fit and break onto their own lines once they do not, and the
last one only takes a semicolon in the broken form. That is what
`CssEmbeddingKind::HtmlStyleAttribute` selects, reusing the snippet root
that already parses a bare declaration list. Such a list ends at the end
of its input rather than at a `}`, so the final semicolon is now
optional there — `style="color: red"` is how everyone writes it.

Two supporting fixes:

The trailing hard line break after embedded content moves from the
`EndEmbedded` tag into the callers that wrap it. A block wants that
break; an attribute value must not have one, since it would force the
attribute onto its own line whatever its length.

The formatter now knows which ranges have a parsed document waiting, as
the JavaScript formatter already did. A hole nothing fills prints as
nothing, so leaving one for a value that was never parsed would silently
empty the attribute.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>