feature: add support to add mutiple sections to the document inc. headers and footers

- write missing tests

src/file/document/body/section-properties/header-reference/header-reference-attributes.ts

@@ -1,5 +1,11 @@
 import { XmlAttributeComponent } from "file/xml-components";
 
+export enum HeaderReferenceType {
+    DEFAULT = "default",
+    FIRST = "first",
+    EVEN = "even",
+}
+
 export interface IHeaderReferenceAttributes {
     type: string;
     id: string;