Simple fix to make PDFs compile again.

Author: myroslav

docs/source/conf.py

@@ -58,7 +58,7 @@
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
-#language = None
+language = 'uk_UA'
 
 # There are two options for replacing |today|: either, you set today to some
 # non-false value, then it is used: