syntax_data: {"ast_node_type":"other","tokens":[{"end":66,"kind":"keyword","start":0,"text":"unpretty:"}]}
source_snippet:     unpretty: Option<String> = (None, parse_unpretty, [UNTRACKED],
context_before:         "take the brakes off const evaluation. NOTE: this is unsound (default: no)"),
context_after:         "present the input source, unstable (and less-pretty) variants;