message: [Common APIs] Add before close notification dialog code sample
diff: @@ -218,6 +218,22 @@ Office.Auth#getAccessTokenAsync:member(1):
  console.log("Error obtaining token", result.error);
  }
  });
  +Office.BeforeDocumentCloseNotification:interface:
  + - |-
  + // Enable the before close modal notification dialog.
  + async function enableNotification() {
  + await Office.addin.beforeDocumentCloseNotification.enable();
  + }
  +
  + // Add an event handler to detect when the document close operation is cancelled.
  + Office.addin.beforeDocumentCloseNotification.onCloseActionCancelled(async function () {
  + // When the document close attempt is cancelled, write a message to the active range in the worksheet.
  + await Excel.run(async (context) => {
  + const range = context.workbook.getSelectedRange();
  + range.values = [["Detected onCloseActionCancelled event."]];
  + await context.sync();
  + });
  + });
  Office.Binding#addHandlerAsync:member(2):
  - |-
  // The following code sample calls the select method of the Office object to access the binding
  