go/printer: mention that input file is formatted in TestFiles error message
Currently when one of the tests in TestFiles fail, then the error looks
like this:
--- testdata/generics.input
+++ testdata/generics.golden
which is confusing, with this change it will be:
--- format(testdata/generics.input)
+++ testdata/generics.golden
Change-Id: Id5c080c5237acd82303d2f41cace8a3fe9ea08e0
GitHub-Last-Rev:
aedafc05fd2fa9dd234188fd710ecf0c924f597a
GitHub-Pull-Request: golang/go#69292
Reviewed-on: https://go-review.googlesource.com/c/go/+/610559
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Robert Griesemer <gri@google.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>