syntax_data: {"ast_node_type":"other","tokens":[{"end":93,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// If "self" is the span of the outer_ident, and "within" is the span of the `($ident,)`
context_before:     ///
context_after:     /// expr, then this will return the span of the `$ident` macro variable.