We silently fix missing #optional tags for QAPIDoc by appending a line
"#optional" to the section's .content. However, this interferes with
.__repr__ stripping trailing blank lines from .content.
Use new ArgSection instance variable .optional instead, and leave
.content alone.
To permit testing .optional in texi_body(), clean up texi_enum()'s
hack to add empty documentation for undocumented enum values: add an
ArgSection instead of ''.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <1489582656-31133-12-git-send-email-armbru@redhat.com>