exclude linted files in fixtures when formatting

Author: lilnasy

oxfmtrc.jsonc

@@ -8,7 +8,7 @@
     "**/generated/**",
     // Ignore `fixtures` directories except for `apps/oxlint/test/fixtures`
     "**/fixtures/**",
-    "!apps/oxlint/test/fixtures/**",
+    "!apps/oxlint/test/fixtures/**/plugin.ts",
     "tasks/coverage/node-compat-table",
     "tasks/coverage/misc",
     "tasks/coverage/src/runtime/babelHelpers.js",