nip22: fix example type for external URL (#2011)

22.md

@@ -143,13 +143,13 @@ A comment on a website's url looks like this:
   "tags": [
     // referencing the root url
     ["I", "https://abc.com/articles/1"],
-    // the root "kind": for an url, the kind is its domain
-    ["K", "https://abc.com"],
+    // the root "kind": for an url
+    ["K", "web"],
 
     // the parent reference (same as root for top-level comments)
     ["i", "https://abc.com/articles/1"],
-    // the parent "kind": for an url, the kind is its domain
-    ["k", "https://abc.com"]
+    // the parent "kind": for an url
+    ["k", "web"]
   ]
   // other fields
 }