Set default language in conf.tmpl

language is passed on to sphinx and used to set lang attr on the html tag - imnportant to give it a meaningful value

Author: ascholerChemeketa

runestone/common/project_template/conf.tmpl

@@ -61,8 +61,8 @@ version = '0.0.1'
 release = '0.0'
 
 # The language for content autogenerated by Sphinx. Refer to documentation
-# for a list of supported languages.
-#language = None
+# for a list of supported languages. https://www.sphinx-doc.org/en/master/usage/configuration.html
+language = "en"
 
 # There are two options for replacing |today|: either, you set today to some
 # non-false value, then it is used: