Handle Webp Image Uploads

With this fix, uploaded WebP images render as links in the markdown (vs images).

src/js/easymde.js

@@ -901,7 +901,7 @@ function afterImageUploaded(editor, url) {
     var ext = imageName.substring(imageName.lastIndexOf('.') + 1).replace(/\?.*$/, '').toLowerCase();
 
     // Check if media is an image
-    if (['png', 'jpg', 'jpeg', 'gif', 'svg'].includes(ext)) {
+    if (['png', 'jpg', 'jpeg', 'gif', 'svg', 'webp'].includes(ext)) {
         _replaceSelection(cm, stat.image, options.insertTexts.uploadedImage, url);
     } else {
         var text_link = options.insertTexts.link;