String indices validity

[xwu (Xiaodi Wu)]

@taylorswift

how does one obtain a canonicalized array of UTF-8 data?

Well...

String case folding and normalization APIs

[NOTE: I'm posting this on behalf of @xwu, who authored this proposal and asked me to push it forward due to personal time constraints. It aligns nicely with some of my other Unicode interests, and I think it would be a non-intrusive and valuable addition to the string handling facilities of the standard library.] Proposal text: String case folding and normalization APIs · GitHub Initial implementation: apple/swift#17933 cc: @Michael_Ilseman Introduction We propose to add APIs for case f…