[String] Fix quotes

OskarStark · OskarStark · commit 3d634fa9add3 · 2020-02-13T09:03:12.000+01:00
diff --git a/components/string.rst b/components/string.rst
@@ -121,7 +121,7 @@ to make your code more concise::
     use function Symfony\Component\String\s;
 
     // creates a ByteString object
-    $foo = s('\xfe\xff');
+    $foo = s("\xfe\xff");
     // creates a UnicodeString object
     $foo = s('अनुच्छेद');
 
