diff --git a/docs/source/conf.py b/docs/source/conf.py
index 1db1f332..47c8b487 100644
--- a/docs/source/conf.py
+++ b/docs/source/conf.py
@@ -53,7 +53,7 @@
 # The suffix(es) of source filenames.
 # You can specify multiple suffix as a list of string:
 # source_suffix = ['.rst', '.md']
-source_suffix = ".rst"
+source_suffix = {".rst": "restructuredtext"}
 
 # Add dev disclaimer.
 if version_info[-1] == "dev":