syntax_data: {"ast_node_type":"function","tokens":[{"end":65,"kind":"keyword","start":0,"text":"pub"}]}
source_snippet:     pub fn span_to_diagnostic_string(&self, sp: Span) -> String {
context_before:     /// for string suitable for embedding.
context_after:         self.span_to_string(sp, self.path_mapping.filename_display_for_diagnostics)