yat2m: Interpret -- and --- verbatimly in @example.
* doc/yat2m.c (example_cmd_active): New. (proc_texi_cmd): Don't apply the processing for en-dash and em-dash when it's in @example/@smallexample.
- GnuPG-bug-id: T6746
- Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>