`@argcheck` false positive

[ericphanson]

in some private code I am seeing a FP around @argcheck:

  Test threw exception
  Expression: check_no_implicit_imports(MyPkg) === nothing
  ImplicitImportsException
  Module `MyPkg` is relying on the following implicit imports:
  * `@argcheck` which is exported by ArgCheck
  

The module indeed has an @argcheck ... invocation.