Display forms only on default post types

[MAILPOET-2639]

lib/WP/Functions.php

@@ -232,6 +232,10 @@ class Functions {
     return get_post_types($args, $output, $operator);
   }
 
+  public function getPostType($post = null) {
+    return get_post_type($post);
+  }
+
   public function getPosts(array $args = null) {
     return get_posts($args);
   }
@@ -590,6 +594,14 @@ class Functions {
     return is_page($page);
   }
 
+  /**
+   * @param string|array $postTypes Optional. Post type or array of post types. Default empty.
+   * @return bool Whether the query is for an existing single post of any of the given post types.
+   */
+  public function isSingular($postTypes = ''): bool {
+    return is_singular($postTypes);
+  }
+
   /**
    * @param string $package
    * @param array $args