syntax_data: {"ast_node_type":"other","tokens":[{"end":77,"kind":"keyword","start":0,"text":"///"}]}
source_snippet: /// takes up 8 bytes, with less space for the length, parent and context. The
context_before: /// [`SpanData`] is 16 bytes, which is too big to stick everywhere. `Span` only
context_after: /// vast majority (99.9%+) of `SpanData` instances can be made to fit within