docs(cdk/drag-drop): clarify usage; to drag a CdkDrag instance (#20044)

(cherry picked from commit dd02735)

Author: Splaktar

src/cdk/drag-drop/directives/drag-handle.ts

@@ -28,7 +28,7 @@ import {toggleNativeDragInteractions} from '../drag-styling';
  */
 export const CDK_DRAG_HANDLE = new InjectionToken<CdkDragHandle>('CdkDragHandle');
 
-/** Handle that can be used to drag and CdkDrag instance. */
+/** Handle that can be used to drag a CdkDrag instance. */
 @Directive({
   selector: '[cdkDragHandle]',
   host: {