dedupe ignore list that already ignored by vcs integration

Author: cometkim

.gitignore

@@ -93,3 +93,6 @@ playground/*.cmj
 playground/*.cmi
 playground/.netrc
 playground/compiler.js
+
+rewatch/target/
+rewatch/rewatch

biome.json

@@ -21,17 +21,14 @@
     "lineWidth": 80,
     "attributePosition": "auto",
     "ignore": [
-      "_build/**",
-      "_opam/**",
       "jscomp/build_tests/**/lib/**",
       "jscomp/build_tests/**/*.bs.js",
       "jscomp/build_tests/**/*.res.js",
       "jscomp/test/*.js",
       "lib/**",
       "ninja/**",
-      "package.json",
       "playground/**",
-      "rewatch/target/**"
+      "package.json"
     ]
   },
   "javascript": {