Add supporting themes required for Lotusdocs

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

@@ -0,0 +1,21 @@
+// @flow
+import getNodeName from './getNodeName';
+import getDocumentElement from './getDocumentElement';
+import { isShadowRoot } from './instanceOf';
+
+export default function getParentNode(element: Node | ShadowRoot): Node {
+  if (getNodeName(element) === 'html') {
+    return element;
+  }
+
+  return (
+    // this is a quicker (but less type safe) way to save quite some bytes from the bundle
+    // $FlowFixMe[incompatible-return]
+    // $FlowFixMe[prop-missing]
+    element.assignedSlot || // step into the shadow DOM of the parent of a slotted node
+    element.parentNode || // DOM Element detected
+    (isShadowRoot(element) ? element.host : null) || // ShadowRoot detected
+    // $FlowFixMe[incompatible-call]: HTMLElement is a Node
+    getDocumentElement(element) // fallback
+  );
+}