[Sema] Add implicit @_hasStorage attribute for printing

tools/SourceKit/lib/SwiftLang/SwiftLangSupport.cpp

@@ -688,6 +688,7 @@ Optional<UIdent> SwiftLangSupport::getUIDForDeclAttribute(const swift::DeclAttri
     case DAK_ShowInInterface:
     case DAK_RawDocComment:
     case DAK_HasInitialValue:
+    case DAK_HasStorage:
       return None;
     default:
       break;