Some --filter descriptions listed the filters with asterisks,
i.e. markdown italics. There were 60+ of those, 250+ without
asterisks, so I choose to de-asterisk them all. Update the
xref script to remove the allow-asterisk exception. (Except
for the column title, which is sometimes written with two
asterisks--boldface--and sometimes plain).
Signed-off-by: Ed Santiago <santiago@redhat.com>
a80a908df7