Function emit_attribute_node 

pub fn emit_attribute_node(builder: &mut impl InlineSink, raw_attr_text: &str)

Emit a Pandoc {...} ATTRIBUTE node by STRUCTURING the raw source slice into ATTR_* children that wrap the original bytes (no synthesis). Markers and quotes stay inside their tokens; whitespace/newlines between components, and any bytes the scanner skips (duplicate #id, malformed tokens), become standalone WHITESPACE/NEWLINE/TEXT tokens — so node.text() is exactly the source slice. Non-{...}-shaped or unrecognized input (MMD [#id] header brackets, raw-inline {=format}, empty {}) falls back to a single opaque ATTRIBUTE token, preserving the prior shape.