syntax_data: {"ast_node_type":"other","tokens":[{"end":94,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// Each expansion should have an associated expansion data, but sometimes there's a delay
context_before: pub(crate) struct HygieneData {
context_after:     /// between creation of an expansion ID and obtaining its data (e.g. macros are collected