This is needed on systems that ship with groff versions older than 1.20;
such as macOS up thru Sierra (10.12). See fish issue #2673.

For UTF-8, map some characters conservatively for the sake
of easy cut and paste.
. . rchar - - ' ` . . char - \N'45' . char - \N'45' . char ' \N'39' . char ` \N'96' .\}