Avoid usage of Enumeration.toString (issues with GraalVM)

src/main/scala/sangria/introspection/package.scala

@@ -250,7 +250,7 @@ package object introspection {
     fields = fields[Unit, Directive](
       Field("name", StringType, resolve = _.value.name),
       Field("description", OptionType(StringType), resolve = _.value.description),
-      Field("locations", ListType(__DirectiveLocation), resolve = _.value.locations.toVector.sortBy(_.toString)),
+      Field("locations", ListType(__DirectiveLocation), resolve = _.value.locations.toVector.sorted),
       Field("args", ListType(__InputValue), resolve = _.value.arguments),
       Field("onOperation", BooleanType,
         deprecationReason = Some("Use `locations`."),

src/main/scala/sangria/schema/Schema.scala

@@ -666,29 +666,24 @@ sealed trait HasArguments {
 }
 
 object DirectiveLocation extends Enumeration {
-  // Operations
-
-  val Query = Value
-  val Mutation = Value
-  val Subscription = Value
+  val ArgumentDefinition = Value
+  val Enum = Value
+  val EnumValue = Value
   val Field = Value
+  val FieldDefinition = Value
   val FragmentDefinition = Value
   val FragmentSpread = Value
   val InlineFragment = Value
-
-  // Schema Definitions
-
-  val Schema = Value
-  val Scalar = Value
-  val Object = Value
-  val FieldDefinition = Value
-  val ArgumentDefinition = Value
+  val InputFieldDefinition = Value
+  val InputObject = Value
   val Interface = Value
+  val Mutation = Value
+  val Object = Value
+  val Query = Value
+  val Scalar = Value
+  val Schema = Value
+  val Subscription = Value
   val Union = Value
-  val Enum = Value
-  val EnumValue = Value
-  val InputObject = Value
-  val InputFieldDefinition = Value
 
   def fromString(location: String): DirectiveLocation.Value = location match {
     case "QUERY" ⇒ Query