fix: correct json for announcements file [skip ci]

announcements-extra.json

@@ -1,7 +1,7 @@
 [
-   {
+  {
     "id": "#1227",
     "title": "Issue(macOS): manual update to `1.90.x`",
     "url": "https://github.com/VSCodium/vscodium/issues/1917"
-  },
+  }
 ]