doc/source/conf.py: specify a language to make sphinx happy.

diff --git a/doc/source/conf.py b/doc/source/conf.py
index e69f5ee8d410953668eb43332ceb74fcba8406d9..6b1bfde6a0d816b88cd05de6981cedeb95b4bf54 100644 (file)
--- a/doc/source/conf.py
+++ b/doc/source/conf.py
@@ -50,7 +50,7 @@ release = '0.1.1'
 #
 # 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
+language = "en"
 
 # List of patterns, relative to source directory, that match files and
 # directories to ignore when looking for source files.