Could chpl errors that support a more detailed form prompt about --detailed-errors

[bradcray]

A new user to Chapel may not know about the --detailed-errors flag, though they may benefit from it. This issue asks whether we should have error messages that support a more detailed form end (or start?) with a little message like "For more detail or context on these errors, try recompiling with --detailed-errors" or the like (maybe we'd want to mention the CHPL_ variable as well? Essentially, use the error output as a teaching opportunity for the user since it'd be easy not to know the flag exists.