Fix type hint for case of trusting all proxies (string) (#5025)

app/Http/Middleware/TrustProxies.php

@@ -10,7 +10,7 @@ class TrustProxies extends Middleware
     /**
      * The trusted proxies for this application.
      *
-     * @var array
+     * @var array|string
      */
     protected $proxies;