Add documentation links

ts/docx/paragraph/indent.ts

@@ -1,3 +1,4 @@
+// http://officeopenxml.com/WPindentation.php
 import { XmlAttributeComponent, XmlComponent } from "../xml-components";
 
 interface IIndentAttributesProperties {

ts/docx/paragraph/page-break.ts

@@ -1,3 +1,4 @@
+// http://officeopenxml.com/WPtextSpecialContent-break.php
 import { Run } from "../run";
 import { Attributes, XmlComponent } from "../xml-components";
 

ts/docx/paragraph/properties.ts

@@ -1,3 +1,4 @@
+// http://officeopenxml.com/WPparagraphProperties.php
 import { XmlComponent } from "../xml-components";
 
 export class ParagraphProperties extends XmlComponent {

ts/docx/paragraph/spacing.ts

@@ -1,3 +1,4 @@
+// http://officeopenxml.com/WPspacing.php
 import { XmlAttributeComponent, XmlComponent } from "../xml-components";
 
 export interface ISpacingProperties {

ts/docx/run/break.ts

@@ -1,3 +1,4 @@
+// http://officeopenxml.com/WPtextSpecialContent-break.php
 import { XmlComponent } from "../xml-components";
 
 export class Break extends XmlComponent {