instead of ignoring test files, declaring them as possible entry points (#1480)

Author: Janther

knip.json

@@ -1,8 +1,8 @@
 {
   "$schema": "https://unpkg.com/knip@5/schema.json",
+  "entry": ["tests/**/*.test.js"],
   "ignoreFiles": [
-    "tests/format/RespectDefaultOptions/respect-default-options.js",
-    "tests/integration/**/*.test.js"
+    "tests/format/RespectDefaultOptions/respect-default-options.js"
   ],
   "ignoreDependencies": ["eslint-config-prettier"],
   "ignoreExportsUsedInFile": {