Documentation: render special characters correctly
Three hyphens are rendered verbatim, so "--" has to be used to produce a
dash. There is no double arrow ("<->" is rendered as "<→"), so a left
and right arrow "<-->" have to be combined for that.
So fix asciidoc output for special characters. This is similar to fixes
in commit
de82095a95 (doc hash-function-transition: fix asciidoc output,
2021-02-05).
Signed-off-by: Andrei Rybak <rybak.a.v@gmail.com>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>