fixed markup

diff --git a/doc/internals.rst b/doc/internals.rst
index 4f0fd0b..9a9cb52 100644 (file)
--- a/doc/internals.rst
+++ b/doc/internals.rst
@@ -7,7 +7,7 @@ features and enhancements can be handled with extensions. This chapter is also
 useful for people who want to understand how Twig works under the hood.
 
 How does Twig work?
----------------
+-------------------
 
 The rendering of a Twig template can be summarized into four key steps: