[internal] Tweak jsonc formatting

.vscode/settings.json

@@ -17,6 +17,16 @@
   "zig.buildFilePath": "${workspaceFolder}/build.zig",
   "zig.initialSetupDone": true,
   "editor.formatOnSave": true,
+
+  // We are using biome instead of prettier.
+  "prettier.enable": false,
+
+  "[json]": {
+    "editor.defaultFormatter": "biomejs.biome"
+  },
+  "[jsonc]": {
+    "editor.defaultFormatter": "biomejs.biome"
+  },
   "[zig]": {
     "editor.tabSize": 4,
     "editor.useTabStops": false,

biome.json

@@ -22,6 +22,10 @@
   "json": {
     "formatter": {
       "indentStyle": "space"
+    },
+    "parser": {
+      "allowComments": true,
+      "allowTrailingCommas": true
     }
   },
   "vcs": {