syntax_data: {"ast_node_type":"other","tokens":[{"end":87,"kind":"keyword","start":0,"text":"///"}]}
source_snippet: /// - `span.len_with_tag_or_marker & !PARENT_TAG == len == span_data.hi - span_data.lo`
context_before: /// - `span.lo_or_index == span_data.lo`
context_after: ///   (must be `<= MAX_LEN`)