feat: add fn->url to read more on md generator

Author: Chemaclass

build/src/php/FileGenerator/Application/ApiMarkdownGenerator.php

@@ -24,6 +24,9 @@ public function generate(): array
         foreach ($groupedPhelFns as $fn) {
             $result[] = "## `{$fn->fnName()}`";
             $result[] = $fn->doc();
+            if ($fn->url() !== '') {
+                $result[] = sprintf('Read more [here](%s).', $fn->url());
+            }
         }
 
         return $result;