Preserve block attributes above doctitle of page

This issue request for changes to be made in Antora Assembler to preserve block attributes on the doctitle.

I discovered that this functionality stopped working with beta builds. I had used in my semi-automated-revision-history extension for asciidoctor-pdf, which extends the convert_table and add_outline functions. As discussed in the Zulipchat, the prior behavior of the alpha builds was not intentional. It would be helpful if Antora Assembler could preserve block attributes on level 0 headings, consistent with how it treats other block elements.

chapter-1.adoc

[rhrev1-1="Corrected a typo in URL."]
[rhrev1-2="Incorporated new information from primary sources."]
[#chapter-1]
= Chapter 1

This is sample text

I apologize that I am not familiar with the Antora Assembler source, so I cannot offer a a merge request.

Thank you in advance.