downgrade to kirby v3

kirby/src/Parsley/Schema.php

@@ -18,8 +18,11 @@ class Schema
 	/**
 	 * Returns the fallback block when no
 	 * other block type can be detected
+	 *
+	 * @param \Kirby\Parsley\Element|string $element
+	 * @return array|null
 	 */
-	public function fallback(Element|string $element): array|null
+	public function fallback($element): ?array
 	{
 		return null;
 	}
@@ -27,6 +30,8 @@ class Schema
 	/**
 	 * Returns a list of allowed inline marks
 	 * and their parsing rules
+	 *
+	 * @return array
 	 */
 	public function marks(): array
 	{
@@ -36,6 +41,8 @@ class Schema
 	/**
 	 * Returns a list of allowed nodes and
 	 * their parsing rules
+	 *
+	 * @return array
 	 */
 	public function nodes(): array
 	{
@@ -45,6 +52,8 @@ class Schema
 	/**
 	 * Returns a list of all elements that should be
 	 * skipped and not be parsed at all
+	 *
+	 * @return array
 	 */
 	public function skip(): array
 	{