diffsum: display msgid for queries

Knowing the specific message ID can be useful for debugging purposes.
The displayed value is the actually message ID contained in the query,
not the respdiff's internal query ID (QID) used for identification in
LMDB.
5 jobs for diffsum-msgid in 1 minute and 27 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Test
passed #497388
amd64 linux docker
test:flake8

00:00:23

passed #497387
amd64 linux docker
test:mypy

00:00:36

passed #497389
amd64 linux docker
test:pylint

00:00:44

passed #497390
amd64 linux docker
test:pytest

00:00:26

passed #497391
amd64 linux docker
test:respdiff

00:01:26