MlkBookmarkSubmissionForm: Make type-only import Flow-commented.

Change-Id: Ie1b6461e5ae8ef7888412a4cfbc3d9543a2ddbeb
diff --git a/src/main/resources/META-INF/resources/bookmarks/MlkBookmarkSubmissionForm.js b/src/main/resources/META-INF/resources/bookmarks/MlkBookmarkSubmissionForm.js
index 520aa32..0a8fad7 100644
--- a/src/main/resources/META-INF/resources/bookmarks/MlkBookmarkSubmissionForm.js
+++ b/src/main/resources/META-INF/resources/bookmarks/MlkBookmarkSubmissionForm.js
@@ -1,6 +1,6 @@
 // @flow
 
-import ProgressSpinner from "../web_modules/elix/define/ProgressSpinner.js";
+import /*:: ProgressSpinner from */ "../web_modules/elix/define/ProgressSpinner.js";
 import { cast } from "../cms2/types.js";
 
 const template = document.createElement('template');