gh-114231: Fix indentation in enum.rst (#114232)

Author: miyashiiii

Doc/library/enum.rst

@@ -838,7 +838,7 @@ Utilities and Decorators
 
    * ``FIRST = auto()`` will work (auto() is replaced with ``1``);
    * ``SECOND = auto(), -2`` will work (auto is replaced with ``2``, so ``2, -2`` is
-      used to create the ``SECOND`` enum member;
+     used to create the ``SECOND`` enum member;
    * ``THREE = [auto(), -3]`` will *not* work (``<auto instance>, -3`` is used to
      create the ``THREE`` enum member)