Fix two oversights in C API split.

Doc/c-api/gcsupport.rst

@@ -18,6 +18,7 @@ include the :const:`Py_TPFLAGS_HAVE_GC` and provide an implementation of the
 
 
 .. data:: Py_TPFLAGS_HAVE_GC
+   :noindex:
 
    Objects with a type with this flag set must conform with the rules documented
    here.  For convenience these objects will be referred to as container objects.

Doc/c-api/index.rst

@@ -24,4 +24,4 @@ document the API functions in detail.
    concrete.rst
    init.rst
    memory.rst
-   newtypes.rst
+   objimpl.rst