doc,version: Fix copyright notices

(cherry picked from commit 57e0dfc)
Signed-off-by: LIU Hao <lh_mouse@126.com>

Author: lhmouse

mcfgthread/version.rc

@@ -37,7 +37,7 @@ VS_VERSION_INFO VERSIONINFO
         VALUE "FileVersion",      _MCF_ABI_VERSION_STRING
         VALUE "FileDescription",  "Cornerstone of the MOST efficient std::thread on Windows"
         VALUE "CompanyName",      "LH_Mouse"
-        VALUE "LegalCopyright",   "Copyleft 2022 - 2024, LH_Mouse. All wrongs reserved."
+        VALUE "LegalCopyright",   "Copyright (C) 2022 - 2024, LH_Mouse. All wrongs reserved."
         VALUE "Comments",         "https://github.com/lhmouse/mcfgthread"
       }
     }

mutex_performance.c

@@ -1,9 +1,6 @@
-/* This file is part of MCF Gthread.
- * Copyright (C) 2022-2024 LH_Mouse. All wrongs reserved.
- *
- * MCF Gthread is free software. Licensing information is included in
- * LICENSE.TXT as a whole. The GCC Runtime Library Exception applies
- * to this file.  */
+/* This file is licensed under CC0 for illustrative purposes. You can
+ * do whatever you like with this piece of code. Any warranty, explicit
+ * or implicit, is disclaimed.  */
 
 #include <math.h>
 #include <stdio.h>