Made demo files into typescript files

demo/demo16.ts

@@ -0,0 +1,40 @@
+// Multiple sections and headers
+// Import from 'docx' rather than '../build' if you install from npm
+import * as fs from "fs";
+import { Document, Packer, PageNumberFormat, PageOrientation, Paragraph } from "../build";
+
+const doc = new Document();
+
+const paragraph = new Paragraph("Hello World").pageBreak();
+
+doc.addParagraph(paragraph);
+
+const header = doc.createHeader();
+header.createParagraph("Header on another page");
+const footer = doc.createFooter();
+footer.createParagraph("Footer on another page");
+
+doc.addSection({
+    headerId: header.Header.ReferenceId,
+    footerId: footer.Footer.ReferenceId,
+    pageNumberStart: 1,
+    pageNumberFormatType: PageNumberFormat.DECIMAL,
+});
+
+doc.createParagraph("hello");
+
+doc.addSection({
+    headerId: header.Header.ReferenceId,
+    footerId: footer.Footer.ReferenceId,
+    pageNumberStart: 1,
+    pageNumberFormatType: PageNumberFormat.DECIMAL,
+    orientation: PageOrientation.LANDSCAPE,
+});
+
+doc.createParagraph("hello in landscape");
+
+const packer = new Packer();
+
+packer.toBuffer(doc).then((buffer) => {
+    fs.writeFileSync("My Document.docx", buffer);
+});