Unexpected error message on stderr when running `Extraction TestCompile`

Submitting this as per the error message's request. ``` Coqtail received an unexpected error message on stderr. Please report at https://github.com/whonore/Coqtail/issues. This can sometimes happen if the message is actually a warning, but is not formatted in a way that Coqtail recognizes. If you wish to ignore this error and try to proceed past it, set g:coqtail_treat_stderr_as_warning = 1. From stderr: File "/tmp/testextractiondcafc6.mli", line 74, characters 36-43: 74 | val eqb : positive -> positive -> sumbool ^^^^^^^ Error: Unbound type constructor sumbool Hint: Did you mean bool? ```