add versionadded on tree.rst

Author: smnandre

Diff for: components/console/helpers/tree.rst

@@ -3,6 +3,10 @@ Tree Helper
 
 The Tree Helper allows you to build and display tree structures in the console.
 
+.. versionadded:: 7.3
+
+    The TreeHelper class was introduced in Symfony 7.3.
+
 Rendering a Tree
 ----------------