Make constraint invocations nameable

[mattdailis]

Checked for duplicates

No - I haven't checked

Alternatives considered

No - I haven't considered

Related problems

No response

Describe the feature request

Mousing over a constraint violation shows the constraint name, but if there are multiple invocations of that constraint, it's not clear which invocation resulted in the violation.

It would be useful to be able to name individual constraint invocations, and for that name to appear when you mouse over its violations.