Fix indentation

Author: cmaloney

development-tools/clinic/howto.rst

@@ -876,7 +876,7 @@ Just name them ``__new__`` or ``__init__`` as appropriate.  Notes:
   generated will throw an exception if it receives any.)
 
 * :ref:`vectorcall protocol <python:vectorcall>` support can be added using the
-``@vectorcall`` directive. This will output an additional function that can be
+  ``@vectorcall`` directive. This will output an additional function that can be
   used in the :c:member:`~PyTypeObject.tp_vectorcall` slot. Vectorcall adds
   moderate code, be sure to microbenchmark and validate it saves significant
   runtime.