Fix issue with keys in documents when rerendering

Not all projects use the file names in the compiler results. So
we need to replace the correct item finding it by path. We use the
array_find_key function of php for this. Since we support older
php versions a polyfill is needed.

Author: jaapio

composer.json

@@ -50,7 +50,8 @@
         "phpdocumentor/guides-markdown": "^1.0 || ^1.0@dev",
         "phpdocumentor/guides-restructured-text": "^1.0 || ^1.0@dev",
         "phpdocumentor/guides-theme-bootstrap": "^1.0 || ^1.0@dev",
-        "phpdocumentor/guides-theme-rst": "^1.0 || ^1.0@dev"
+        "phpdocumentor/guides-theme-rst": "^1.0 || ^1.0@dev",
+        "symfony/polyfill-php84": "^1.33"
     },
     "require-dev": {
         "ext-dom": "*",