Fix comment typo (#171)

diff --git a/examples/rewrite_ast.py b/examples/rewrite_ast.py
index 7d1b196..eae6539 100644
--- a/examples/rewrite_ast.py
+++ b/examples/rewrite_ast.py
@@ -1,5 +1,5 @@
 #-----------------------------------------------------------------
-# pycparser: func_write.py
+# pycparser: rewrite_ast.py
 #
 # Tiny example of rewriting a AST node
 #