(If you are dealing with a generated constraint name like $2, don't forget that you'll need to double-quote it to make it a valid identifier.)
If I have a constraint with the name $2, are there other constraints with names $1, $3 ... ?
I feel like that whole parenthetical should just go away. The point of the comment is to remind the user of how identifier values work with respect to mandatory double quoting. The name itself, other than having a $, has no special importance.
