syntax_data: {"ast_node_type":"other","tokens":[{"end":64,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// - it also appears in the backtrace at some position `X`,
context_before:     /// - is a coinductive trait: an auto-trait or `Sized`,
context_after:     /// - all the predicates at positions `X..` between `X` and the top are