Fix order of NEWGROUPS

RFC 3977 provides the following example for NEWGROUPS:

  [C] NEWGROUPS 19990624 000000 GMT
  [S] 231 list of new newsgroups follows
  [S] alt.rfc-writers.recovery 4 1 y
  [S] tx.natives.recovery 89 56 y
  [S] .

https://datatracker.ietf.org/doc/html/rfc3977#section-7.3.3

The order is "higher number comes first".

Fixes #601107.