Return a Formatter for a (potentially ill-formed) UTF-8 string. Ill-formed UTF-8 byte sequences are replaced by the replacement character (U+FFFD) according to "U+FFFD Substitution of Maximal Subparts" from Chapter 3 of the Unicode standard, and as specified by https://encoding.spec.whatwg.org/#utf-8-decoder
pub fn fmtUtf8(utf8: []const u8) std.fmt.Alt([]const u8, formatUtf8)
pub fn fmtUtf8(utf8: []const u8) std.fmt.Alt([]const u8, formatUtf8) {
return .{ .data = utf8 };
}