chore: fix end of files & trailing whitespace

docs/static/_headers

@@ -3,4 +3,4 @@
   Content-Type: application/json
 /.well-known/continuwuity/*
   Access-Control-Allow-Origin: *
-  Content-Type: application/json
+  Content-Type: application/json

docs/static/announcements.schema.json

@@ -32,4 +32,4 @@
     "required": [
       "announcements"
     ]
-  }
+  }

docs/static/support

@@ -21,4 +21,4 @@
     }
   ],
   "support_page": "https://continuwuity.org/introduction#contact"
-}
+}