and curly braces, since the current cmtt font seems to support these characters better than it once did. csug/scheme.sty release_notes/scheme.sty original commit: f6c57b55cfbe34b269a606bd96983d62191a9aa1
original commit: 21ca187a89c743bc7fab9a8b9f1996dcf9418c8d
original commit: 47a210c15c63ba9677852269447bd2f2598b51fe