Remove unnecessary grammar decorations and change header (GH-20819) (GH-22101)

(cherry picked from commit b4282dd15079ed46edc9d382b21422320a0af94f)

Co-authored-by: Pablo Galindo <Pablogsal@gmail.com>
diff --git a/Grammar/python.gram b/Grammar/python.gram
index 44d435c..334a7f5 100644
--- a/Grammar/python.gram
+++ b/Grammar/python.gram
@@ -1,6 +1,5 @@
-# Simplified grammar for Python
+# PEG grammar for Python
 
-@bytecode True
 @trailer '''
 void *
 _PyPegen_parse(Parser *p)