In this day and age, it is perfectly reasonable to tell people use an editor that supports Unicode and the UTF-8 encoding.
(Julia doesn’t even run on ancient systems where a lack of Unicode support might be hard to circumvent. And the only still-extant text editors I can find that don’t support unicode are ed and pico, and no sane programmer would use either of these…are there any other examples?)
Correction: apparently there may be one popular programming text editor that still doesn’t properly support Unicode, and that is the Matlab editor. But if you are using the Matlab editor to write Julia code then you may need to re-think your life choices.