[T] Declaration

type Declaration: 
  | ModelStatementNode
  | ScalarStatementNode
  | InterfaceStatementNode
  | UnionStatementNode
  | NamespaceStatementNode
  | OperationStatementNode
  | TemplateParameterDeclarationNode
  | ProjectionStatementNode
  | ProjectionParameterDeclarationNode
  | ProjectionLambdaParameterDeclarationNode
  | EnumStatementNode
  | AliasStatementNode
  | ConstStatementNode
  | DecoratorDeclarationStatementNode
  | FunctionDeclarationStatementNode;