Fix spelling of "margin"

src/file/table/table-cell/cell-margin/cell-margin.ts

@@ -0,0 +1,63 @@
+// http://officeopenxml.com/WPtableCellProperties-Margins.php
+import { XmlAttributeComponent, XmlComponent } from "file/xml-components";
+
+export interface ICellMarginProperties {
+    readonly type: string;
+    readonly width: number;
+}
+
+class CellMarginAttributes extends XmlAttributeComponent<ICellMarginProperties> {
+    protected readonly xmlKeys = { width: "w:w", type: "w:type" };
+}
+
+export class TopCellMargin extends XmlComponent {
+    constructor(value: number) {
+        super("w:top");
+
+        this.root.push(
+            new CellMarginAttributes({
+                width: value,
+                type: "dxa",
+            }),
+        );
+    }
+}
+
+export class BottomCellMargin extends XmlComponent {
+    constructor(value: number) {
+        super("w:bottom");
+
+        this.root.push(
+            new CellMarginAttributes({
+                width: value,
+                type: "dxa",
+            }),
+        );
+    }
+}
+
+export class LeftCellMargin extends XmlComponent {
+    constructor(value: number) {
+        super("w:start");
+
+        this.root.push(
+            new CellMarginAttributes({
+                width: value,
+                type: "dxa",
+            }),
+        );
+    }
+}
+
+export class RightCellMargin extends XmlComponent {
+    constructor(value: number) {
+        super("w:end");
+
+        this.root.push(
+            new CellMarginAttributes({
+                width: value,
+                type: "dxa",
+            }),
+        );
+    }
+}