...and only include it if `english` or `german` is used.
Since 3d8f011, the babel language is not specified as a
class option any more; so now we need to explicitly specify
the language option when we load `selnolig`. Only `german`
and `english` are valid, so we construct the variable
`selnolig-langs` in the writer and include `selnolig` if it
is nonempty.
This should restore proper ligature suppression when
lualatex is used.
Closes#9863. Supersedes #9864.
Thanks to @fkohrt for the initial fix.
John MacFarlane
cd9753d4af