Don't fail on extlinks warnings for reno build

With Sphinx==4.4.0 some "helpful" warnings were introduced when an
external link could be replaced by a macro, like for :lpbug:. Sadly we
have a very high number of existing release notes that trigger these
warnings and no good way to fix them retrospectively, because would mess
up their mapping to releases. So we change the logging for the
sphinx.ext.extlinks to ignore these warnings for now.

Signed-off-by: Dr. Jens Harbott <harbott@osism.tech>
Change-Id: I709de5e454434b8790a68d9e67ca1432387b21ab

Author: osfrickler

releasenotes/source/conf.py

@@ -37,6 +37,14 @@
 # Add any Sphinx extension module names here, as strings. They can be
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
 # ones.
+from sphinx.util import logging
+
+# According to the discussion in
+# https://github.com/sphinx-doc/sphinx/issues/10112 this may be applied as a
+# dirty hack until the issue with replacing extlinks is resolved
+linklogger = logging.getLogger('sphinx.ext.extlinks')
+linklogger.setLevel(40) # Ignore messages less severe than ERROR
+
 extensions = [
     'openstackdocstheme',
     'reno.sphinxext',