Safari 15.5 shipped html.global_attributes.a.nonce_hiding (#25455)

`html.global_attributes.a.nonce_hiding` shipped in Safari 15.5

References:

- https://developer.apple.com/documentation/safari-release-notes/safari-15_5-release-notes#:~:text=Fixed%20nonce%20hiding%20from%20the%20DOM
- https://bugs.webkit.org/show_bug.cgi?id=179728

html/global_attributes.json

@@ -888,6 +888,7 @@
         "nonce_hiding": {
           "__compat": {
             "description": "`nonce` hiding behavior",
+            "spec_url": "https://html.spec.whatwg.org/multipage/urls-and-fetching.html#nonce-does-not-update-dom",
             "support": {
               "chrome": {
                 "version_added": "61"
@@ -905,8 +906,7 @@
               "opera": "mirror",
               "opera_android": "mirror",
               "safari": {
-                "version_added": false,
-                "impl_url": "https://webkit.org/b/179728"
+                "version_added": "15.5"
               },
               "safari_ios": "mirror",
               "samsunginternet_android": "mirror",