docs: avoid token-like placeholder

Author: goanpeca

scripts/check_listings_api.py

@@ -21,7 +21,7 @@
     python scripts/check_listings_api.py
     python scripts/check_listings_api.py --json
     python scripts/check_listings_api.py --report dist/listings-api.md
-    GITHUB_TOKEN=ghp_... python scripts/check_listings_api.py     # higher rate limits
+    GITHUB_TOKEN=your-token python scripts/check_listings_api.py  # higher rate limits
 
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