[stdlib] Set, Dictionary: Remove inappropriate @_effects from Index hashing

Author: lorentey

stdlib/public/core/Dictionary.swift

@@ -1897,8 +1897,8 @@ extension Dictionary.Index: Comparable {
 }
 
 extension Dictionary.Index: Hashable {
-  @_effects(readonly) // FIXME(cocoa-index): Make inlinable
-  public func hash(into hasher: inout Hasher) {
+  public // FIXME(cocoa-index): Make inlinable
+  func hash(into hasher: inout Hasher) {
   #if _runtime(_ObjC)
     switch _variant {
     case .native(let nativeIndex):

stdlib/public/core/Set.swift

@@ -1418,8 +1418,8 @@ extension Set.Index: Hashable {
   ///
   /// - Parameter hasher: The hasher to use when combining the components
   ///   of this instance.
-  @_effects(readonly) // FIXME(cocoa-index): Make inlinable
-  public func hash(into hasher: inout Hasher) {
+  public // FIXME(cocoa-index): Make inlinable
+  func hash(into hasher: inout Hasher) {
   #if _runtime(_ObjC)
     switch _variant {
     case .native(let nativeIndex):