refactor: fix php-cs-fixer error

spec/Gaufrette/FileSpec.php

@@ -78,7 +78,7 @@ function it_sets_content_of_file(Filesystem $filesystem, MetadataAdapter $adapte
         $filesystem->write('filename', 'some content', true)->shouldBeCalled()->willReturn(21);
 
         $this->setContent('some content')->shouldReturn(21);
-        $this->getContent('filename')->shouldReturn('some content');
+        $this->getContent()->shouldReturn('some content');
     }
 
     function it_sets_key_as_name_by_default()

src/Gaufrette/Filesystem.php

@@ -17,7 +17,7 @@ class Filesystem implements FilesystemInterface
     /**
      * Contains File objects created with $this->createFile() method.
      *
-     * @var array<string, string|File>
+     * @var array<string, File>
      */
     protected array $fileRegister = [];
 

src/Gaufrette/Util/Path.php

@@ -17,7 +17,12 @@ public static function normalize(string $path): string
         $path = str_replace('\\', '/', $path);
         $prefix = static::getAbsolutePrefix($path);
         $path = substr($path, strlen($prefix));
-        $parts = array_filter(explode('/', $path), 'strlen');
+        $parts = array_filter(
+            explode('/', $path),
+            function (string $part): bool {
+                return '' !== $part;
+            },
+        );
         $tokens = [];
 
         foreach ($parts as $part) {