Add additional breaking changes / fixes of note to migration page
The following discussion from !645 (merged) should be addressed:
@mojavelinux started a discussion: (+1 comment)
Additional breaking changes / fixes:
- remove the 2-character (i.e., "") quote block syntax
- drop verse table cell style (treat as normal table cell) (asciidoctor#3111)
- apply verbatim substitutions to literal paragraphs attached to list item (asciidoctor#3205)
- always use title as xreftext if target block has an empty caption, regardless of xrefstyle value (asciidoctor#3745)
- account for empty positional attribute when parsing attrlist (asciidoctor#3813 and asciidoctor#4033)
- don’t allow AsciiDoc table cell to set document attribute that was unset from the API (exceptions include: compat-mode, toc, showtitle, and notitle) (asciidoctor#4017)
- ensure default document attributes unset in parent document remain unset in AsciiDoc table cell (asciidoctor#2586)
- use attribute, if set, as seed value for counter even if not already registered as a counter (asciidoctor#4014)
- don’t include trailing period, question mark, or exclamation point in target (URL) of autolink (asciidoctor#3860)