Update src/SelectTree.php

Author: CodeWithDennis

src/SelectTree.php

@@ -439,7 +439,7 @@ public function getTree(): Collection|array
     {
         return $this->evaluate($this->buildTree()
             ->when($this->prepend, fn (Collection $tree) => $tree->prepend($this->evaluate($this->prepend)))
-            ->when($this->append, fn(Collection $tree) => $tree->push($this->evaluate($this->append)))
+            ->when($this->append, fn (Collection $tree) => $tree->push($this->evaluate($this->append)))
         );
     }