/// Return a schema for a simple string enumeration.
///
/// The list of possible values is provided in the variable argument list.
///
/// @group schema
///
/// @return {Map}
///
/// @example scss - Usage
///   k-enum-schema('foo', 'bar', 'baz');
///   // Will return a schema expecting one of these three strings.
@function k-enum-schema($values...) {
  @return (
    type: 'string',
    enum: $values
  )
}