Leverage arrow function syntax for closure

Author: tigitz

Filesystem.php

@@ -438,11 +438,9 @@ public function makePathRelative(string $endPath, string $startPath): string
             $startPath = str_replace('\\', '/', $startPath);
         }
 
-        $splitDriveLetter = function ($path) {
-            return (\strlen($path) > 2 && ':' === $path[1] && '/' === $path[2] && ctype_alpha($path[0]))
-                ? [substr($path, 2), strtoupper($path[0])]
-                : [$path, null];
-        };
+        $splitDriveLetter = fn ($path) => (\strlen($path) > 2 && ':' === $path[1] && '/' === $path[2] && ctype_alpha($path[0]))
+            ? [substr($path, 2), strtoupper($path[0])]
+            : [$path, null];
 
         $splitPath = function ($path) {
             $result = [];