Misleading message about error location in BS 7

[fhammerschmidt]

File "  /[redacted]/bs-7-example/src/SampleError.re", line 2, characters 6-6:
Error: Unclosed "{" (opened line 1, column 8)

  We've found a bug for you!
  /[redacted]/bs-7-example/src/SampleError.re
  
  There's been an error running Reason's parser on a file.
  The error location should be slightly above this message.
  Please file an issue on github.com/facebook/reason. Thanks!

I think it is strange now with Reerror in BuckleScript 7.0.0, that the error message still says that

The error location should be slightly above this message

When actually the location is exactly where the error happens (which is really nice)

I would change that to be less confusing, for example

If you cannot locate the error with the help of the message above, the error location should be slightly above this message

But I am not sure whether that is too long?

[bobzhang]

cc @chenglou

[bobzhang]

@fhammerschmidt would you mind send a PR on this error message tweak? thanks