add mdn_url (#22953)

Author: skyclouds2001

api/HTMLScriptElement.json

@@ -45,6 +45,7 @@
       },
       "async": {
         "__compat": {
+          "mdn_url": "https://developer.mozilla.org/docs/Web/API/HTMLScriptElement/async",
           "spec_url": "https://html.spec.whatwg.org/multipage/scripting.html#dom-script-async",
           "support": {
             "chrome": {
@@ -231,6 +232,7 @@
       },
       "defer": {
         "__compat": {
+          "mdn_url": "https://developer.mozilla.org/docs/Web/API/HTMLScriptElement/defer",
           "spec_url": "https://html.spec.whatwg.org/multipage/scripting.html#dom-script-defer",
           "support": {
             "chrome": {