diff --git a/sphinx/environment/adapters/asset.py b/sphinx/environment/adapters/asset.py
index a373205d2..ffa88a10f 100644
--- a/sphinx/environment/adapters/asset.py
+++ b/sphinx/environment/adapters/asset.py
@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 """
     sphinx.environment.adapters.assets
-    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
     Assets adapter for sphinx.environment.