add inflection video

src/content/inflection/inflection-intro.mdx

@@ -6,6 +6,9 @@ import { defaultTextOptions as opts, InlinePs } from "@lingdocs/ps-react";
 import Table from "../../components/Table";
 import InlineInflectionButton from "../../components/InlineInflectionButton";
 import catInflectionGif from "../../images/cat-inflection.gif";
+import VideoPlayer from "../../components/VideoPlayer";
+
+<VideoPlayer src="https://www.youtube.com/watch?v=ZUC13KzhPc0" />
 
 export const singleInflectionHeadRow = [
   <div className="d-flex flex-row flex-align-items-center">