Fix wrong Python highlighting in directory hierarchy code block.
diff --git a/Doc/tutorial/modules.rst b/Doc/tutorial/modules.rst
index bcbb761..1e792d1 100644
--- a/Doc/tutorial/modules.rst
+++ b/Doc/tutorial/modules.rst
@@ -368,7 +368,9 @@
 (such as mixing, adding echo, applying an equalizer function, creating an
 artificial stereo effect), so in addition you will be writing a never-ending
 stream of modules to perform these operations.  Here's a possible structure for
-your package (expressed in terms of a hierarchical filesystem)::
+your package (expressed in terms of a hierarchical filesystem):
+
+.. code-block:: text
 
    sound/                          Top-level package
          __init__.py               Initialize the sound package