Fix mkdocs.yml syntax
diff --git a/mkdocs.yml b/mkdocs.yml
index 0495ba9..5351f6e 100644
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -16,7 +16,7 @@
 
 markdown_extensions:
   - toc:
-    - permalink: True
+      permalink: True
 
 extra_css:
   - extra.css