harmonize indentation

Author: merwok

Doc/reference/datamodel.rst

@@ -854,13 +854,13 @@ Custom classes
          their occurrence in the base class list.
 
       :attr:`~class.__base__`
-          ``__base__`` corresponds to the :c:member:`~PyTypeObject.tp_base` in a
-          type object.  At the C level, Python has a single inheritance model
-          that determines the memory layout of instances.  There is a chain
-          involving base classes that contribute to the instance layout.
-          ``__base__`` is the base class that is involved in that chain.
+         ``__base__`` corresponds to the :c:member:`~PyTypeObject.tp_base` in a
+         type object.  At the C level, Python has a single inheritance model
+         that determines the memory layout of instances.  There is a chain
+         involving base classes that contribute to the instance layout.
+         ``__base__`` is the base class that is involved in that chain.
 
-          .. impl-detail::
+         .. impl-detail::
             The behavior of the ``__base__`` attribute is dependent on the :term:`CPython` implementation.
 
       :attr:`__doc__`