Fix TRUSTED_HOSTS regexp example

Author: guilliamxavier

symfony/framework-bundle/3.3/manifest.json

@@ -15,7 +15,7 @@
         "APP_ENV": "dev",
         "APP_SECRET": "%generate(secret)%",
         "#TRUSTED_PROXIES": "127.0.0.1,127.0.0.2",
-        "#TRUSTED_HOSTS": "'^localhost$|^example\\.com$'"
+        "#TRUSTED_HOSTS": "'^(localhost|example\\.com)$'"
     },
     "gitignore": [
         "/.env.local",