[11.x] Adds missing end-of-line to ServiceProvider::addProviderToBootstrapFile (#49494)

* Adds missing end-of-line

* Apply fixes from StyleCI

---------

Co-authored-by: StyleCI Bot <[email protected]>

Author: nunomaduro

src/Illuminate/Support/ServiceProvider.php

@@ -507,7 +507,7 @@ public static function addProviderToBootstrapFile(string $provider, string $path
 '.$providers.'
 ];';
 
-        file_put_contents($path, $content);
+        file_put_contents($path, $content.PHP_EOL);
 
         return true;
     }