43eb8790f3
Rationale: internally we patch a number of diagnostic messages to add context to messages (and corrections). Introducing maps that allow for customization makes the internal patching process far easier and less prone to error. Change-Id: I2d1e7488b451654dd24b8ae95647619c65d3974b Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/151664 Commit-Queue: Phil Quitslund <pquitslund@google.com> Reviewed-by: Brian Wilkerson <brianwilkerson@google.com> Reviewed-by: David Morgan <davidmorgan@google.com>