Constant XML_SAVE_AS_HTML 

pub const XML_SAVE_AS_HTML: c_int = _; // 64i32

Candidate-internal: nokogiri passes SaveOptions::AS_HTML (64) to emit HTML-style output (HTML-void elements stay <br>-style, non-void empty elements get an explicit end tag). Mirrors nokogiri’s flag value, which is 64 (2^6); upstream uses XML_SAVE_AS_HTML = (1<<10).