Add supporting themes required for Lotusdocs

themes/hugo-mod-jslibs-dist/popperjs/package/lib/dom-utils/getWindow.js.flow

@@ -0,0 +1,16 @@
+// @flow
+import type { Window } from '../types';
+declare function getWindow(node: Node | Window): Window;
+
+export default function getWindow(node) {
+  if (node == null) {
+    return window;
+  }
+
+  if (node.toString() !== '[object Window]') {
+    const ownerDocument = node.ownerDocument;
+    return ownerDocument ? ownerDocument.defaultView || window : window;
+  }
+
+  return node;
+}