...but for now, we'll just use the ascii module to convert to/from upper/lowercase.
I don't think there is any proper external Unicode library that can do this in Hare yet, so the way we will probably want to do this is produce a hash map from these tables:
https://www.ibm.com/docs/en/i/7.2?topic=tables-unicode-lowercase-uppercase-conversion-mapping-table
https://www.ibm.com/docs/en/i/7.1?topic=tables-unicode-uppercase-lowercase-conversion-mapping-table
Since we know all of the values in advance, we could do the hashing and "putting" in advance, and hard-code an array.