Change docx folder to more appropriate "file" folder

src/file/paragraph/formatting/spacing.ts

@@ -0,0 +1,23 @@
+// http://officeopenxml.com/WPspacing.php
+import { XmlAttributeComponent, XmlComponent } from "../../xml-components";
+
+export interface ISpacingProperties {
+    after?: number;
+    before?: number;
+    line?: number;
+}
+
+class SpacingAttributes extends XmlAttributeComponent<ISpacingProperties> {
+    protected xmlKeys = {
+        after: "w:after",
+        before: "w:before",
+        line: "w:line",
+    };
+}
+
+export class Spacing extends XmlComponent {
+    constructor(opts: ISpacingProperties) {
+        super("w:spacing");
+        this.root.push(new SpacingAttributes(opts));
+    }
+}