Issue 34081: Sphinx duplicate label warning in docs

While running make docs sphinx generates a warning that there are duplicate labels named `_examples`. It seems it's present in `c-api/typeobj.rst` and `distutils/examples.rst` as below : 

➜  Doc git:(master) rg '.. _examples:'
c-api/typeobj.rst
2324:.. _examples:

distutils/examples.rst
1:.. _examples:

# Warning

2018-07-10T07:30:36.8709047Z /opt/vsts/work/1/s/Doc/distutils/examples.rst:5: WARNING: duplicate label examples, other instance in /opt/vsts/work/1/s/Doc/c-api/typeobj.rst

Sample log : https://python.visualstudio.com/cpython/cpython%20Team/_build/results?buildId=16141&view=logs

There are no references to the label as far as I have checked and I suppose this is an easy fix to be done if someone wants to take it up. The effect is that in the page https://docs.python.org/3.8/c-api/typeobj.html the following text links to distutils/examples for the text "Examples" which should ideally link to https://docs.python.org/3.8/c-api/typeobj.html#examples

"In addition to the following quick reference, the Examples section provides at-a-glance insight into the meaning and use of PyTypeObject."

It will be also helpful if sphinx warnings are made as an error in CI so that these are caught there.

Thanks

New changeset 121eb1694cab14df857ba6abe9839654cada15cf by Julien Palard (Xtreak) in branch 'master':
bpo-34081: Fix wrong example link that was linking to distutils (GH-8248)
https://github.com/python/cpython/commit/121eb1694cab14df857ba6abe9839654cada15cf