markdown to manpage: Rendering text between ticks not highlighted

[tenzap]

Explain the problem.
Pandoc 3.1.3

Pandoc 3.1.13 (as downloaded from github: *.deb installed on Debian testing)

As you can see, $TMPDIR & /tmp are not highlighted in 3.1.13

Input file:
README.md

**-\-cache=DIR**
:   cache directory (default is `$TMPDIR` or `/tmp`)

Command:

pandoc README.md -s -t man -o debian/mount-zip/usr/share/man/man1/mount-zip.1

Diff of generated manpage:

 preemptively decompress and cache data
 .TP
-\f[B]--cache=DIR\f[R]
-cache directory (default is \f[V]$TMPDIR\f[R] or \f[V]/tmp\f[R])
+\f[B]\-\-cache=DIR\f[R]
+cache directory (default is \f[CR]$TMPDIR\f[R] or \f[CR]/tmp\f[R])
 .TP

I don't know what the rendering should actually be given the input in the readme.md file

[jgm]

Yes, we used to use a custom font name V for emphasis, which we styled as bold in the template, but we had to drop that to produce more portable man pages. (See #9020)