Returns slice of haystack before and after last occurrence of needle,
or null if not found.
See also:
cutsplitScalartokenizeScalarpub fn cutScalarLast(comptime T: type, haystack: []const T, needle: T) ?struct
pub fn cutScalarLast(comptime T: type, haystack: []const T, needle: T) ?struct { []const T, []const T } {
const index = findScalarLast(T, haystack, needle) orelse return null;
return .{ haystack[0..index], haystack[index + 1 ..] };
}