bpo-44345: Fix 'generated by' comment in parser.c (GH-26615)

Author: anonaka

Parser/parser.c

@@ -1,4 +1,4 @@
-// @generated by pegen.py from ./Grammar/python.gram
+// @generated by pegen from ./Grammar/python.gram
 #include "pegen.h"
 
 #if defined(Py_DEBUG) && defined(Py_BUILD_CORE)

Tools/peg_generator/pegen/c_generator.py

@@ -405,7 +405,7 @@ def out_of_memory_goto(self, expr: str, goto_target: str) -> None:
 
     def generate(self, filename: str) -> None:
         self.collect_todo()
-        self.print(f"// @generated by pegen.py from {filename}")
+        self.print(f"// @generated by pegen from {filename}")
         header = self.grammar.metas.get("header", EXTENSION_PREFIX)
         if header:
             self.print(header.rstrip("\n"))