Add language configuration

A missing language configuration is a warning, and thus CI error, in Sphinx 5

Author: jonathansick

conf.py

@@ -32,6 +32,8 @@
 
 # -- General configuration ------------------------------------------------
 
+language = 'en'
+
 # If your documentation needs a minimal Sphinx version, state it here.
 # needs_sphinx = '1.0'
 
@@ -89,13 +91,6 @@
 # The full version, including alpha/beta/rc tags.
 release = version
 
-# The language for content autogenerated by Sphinx. Refer to documentation
-# for a list of supported languages.
-#
-# This is also used if you do content translation via gettext catalogs.
-# Usually you set "language" from the command line for these cases.
-language = None
-
 # There are two options for replacing |today|: either, you set today to some
 # non-false value, then it is used:
 # today = ''