Fix bug where highlighting is not kept when the file has a type error and imports some other file

[janmasrovira]

Example file:

module error;

import empty; -- error only happens if we have at least one import

type T := t;

x : T := t t; -- type error

If one loads this file into emacs (or vscode) they'll get a type error as expected, but name colors and go-to information is lost, which is annoying. This pr fixes this.
I'm not sure why, but this bug only occurs when there is at least one import.