update test asset

crates/apub/assets/lemmy/objects/instance.json

@@ -2,6 +2,7 @@
   "type": "Application",
   "id": "https://enterprise.lemmy.ml/",
   "name": "Enterprise",
+  "preferredUsername": "enterprise.lemmy.ml",
   "summary": "A test instance",
   "content": "<p>Enterprise sidebar</p>\\n",
   "mediaType": "text/html",

crates/apub/src/protocol/objects/instance.rs

@@ -21,7 +21,7 @@ pub struct Instance {
   pub(crate) id: ObjectId<ApubSite>,
   /// site name
   pub(crate) name: String,
-  /// domain, necessary for mastodon authorized fetch
+  /// instance domain, necessary for mastodon authorized fetch
   pub(crate) preferred_username: String,
   pub(crate) inbox: Url,
   /// mandatory field in activitypub, lemmy currently serves an empty outbox