syntax_data: {"ast_node_type":"other","tokens":[{"end":87,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// a diff, prefix them with the "Unit Separator"  control character (␟  U+001F).
context_before:     /// fairly common and may be needed to print a types representation. If using them to indicate
context_after:     fn fmt_diff_with(&self, old: &Self, ctxt: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {