docs: use optimized webp image for ts thumbnail (#607)

* docs: delete large jpeg image

* docs: upload optimized ts_thumbnail image

* chore: use the optimized webp thumbnail

Author: linaseervi

www/public/images/ts_thumbnail.jpeg

@@ -47,7 +47,7 @@ target="_blank">
 
   <p align="center">
     <img
-      src="/images/ts_thumbnail.jpeg"
+      src="/images/ts_thumbnail.webp"
       alt="You might be using TypeScript wrong..."
       width="320"
     />