Fixes#5565, by using tags instead of trying to string match on a
`MessageData`. This ends up reverting some unwanted test output changes
from #4781 too.
This changes `isMaxRecDepth` for good measure too.
This was a regression in Lean 4.11.0, so may be worth backporting to
4.12.x, if not also 4.11.x.
This message is often incorporated into source files via `#guard_msgs`.
This change ensures it won't go over the 100 character ruler, and I
think is equally grammatical. :-)
It is confusing that the message suggesting to use the `diagnostics`
option is given even when the option is already set. This PR makes use
of lazy message data to make the message contingent on the option being
false.
It also tones down the promise that there is any diagonostic information
available, since sometimes there is nothing to report.
Suggested by Johan Commelin.
