Fix case-insensitive handling of .php extensions

Author: sy-records

public/error.php

@@ -181,11 +181,12 @@
     mirror_redirect("https://github.com/php/php-src/issues/" . $matches[1]);
 }
 
-// php.net/supported-versions.PHP -> supported-versions.php
-if ($URI == 'supported-versions.PHP') {
-    mirror_redirect("https://www.php.net/supported-versions.php");
-}
-
+// Fix for case-insensitive .php extension, e.g. /supported-versions.PHP, /downloads.PHP
+$URI = preg_replace_callback(
+    '/\.php\z/i',
+    static fn($match) => strtolower($match[0]),
+    $URI
+);
 
 // ============================================================================
 // Redirect if the entered URI was a PHP page name (except some pages,