Remove useless warning

Doc/c-api/index.rst

@@ -12,12 +12,6 @@ extension modules or embed Python.  It is a companion to :ref:`extending-index`,
 which describes the general principles of extension writing but does not
 document the API functions in detail.
 
-.. warning::
-
-   The current version of this document is somewhat incomplete. However, most of
-   the important functions, types and structures are described.
-
-
 .. toctree::
    :maxdepth: 2