Revert "Update extending.md"

This reverts commit 64b0d4cf068a9d84f8bf74275ffd3f3c84e83ab2.

docs/extending.md

@@ -85,7 +85,7 @@ CMS.registerEditorComponent({
   // Fields the user need to fill out when adding an instance of the component
   fields: [{name: 'id', label: 'Youtube Video ID', widget: 'string'}],
   // Pattern to identify a block as being an instance of this component
-  pattern: /^{{<\s?youtube (\S+)\s?>}}/,
+  pattern: /youtube (\S+)\s/,
   // Function to extract data elements from the regexp match
   fromBlock: function(match) {
     return {
@@ -94,7 +94,7 @@ CMS.registerEditorComponent({
   },
   // Function to create a text block from an instance of this component
   toBlock: function(obj) {
-    return '{{< youtube ' + obj.id + ' >}}';
+    return 'youtube ' + obj.id;
   },
   // Preview output for this component. Can either be a string or a React component
   // (component gives better render performance)