Add trip headsign, route shortname, and stop name to error details

[barbeau]

Summary:

Feedback from agencies - it would be useful to see small details on the entity that triggered the error in the error message. Right now we show the ID, like:

trip_id 1234...

However, it would be more useful if we included the trip headsign, route shortname, and stop name along with the ID, like:

trip_id 1234 South to Downtown

Steps to reproduce:

Trigger an error or warning that includes an entity ID

Expected behavior:

A short human readable description of that entity should be included

Observed behavior:

Only the GTFS ID is included