Alphabetize perltrap

Before 9b12f83b0b6, the programming languages other than Perl were in
alphabetical order.
diag.t: Remove commented obsoleted by 62f5f54dc2d
diag.t: Don’t confuse the two exception listse

The second exception list is for things listed in perldiag whose cate-
gories are in need of correction or are too baffling for diag.t to
check correctly (it’s not very smart).

Due to my careless implementation in commit 62f5f54d, the second list
was also treated effectively as an addendum to the first.  Things not
listed in perldiag could be listed in the second exception list and
make tests pass.
perldiag: Correct severity/category for ‘False [] range’

This can now be a fatal error or a warning.  diag.t is still not
smart enough to verify this, so it is still in its exception list.