Update Copyright year

Author: cjmayo

LICENSE

@@ -3,7 +3,7 @@ This version of Gnofract 4D is distributed under the BSD License.
 Note that earlier versions (versions 1.0 to 1.9 inclusive) were
 distributed under the GNU GPL.
 
-Copyright (c) 1999-2021, Edwin Young
+Copyright (c) 1999-2025, Edwin Young
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without

fract4dgui/application_window.py

@@ -161,7 +161,7 @@ def about(self, *args):
             modal=True,
             comments=_("Easy to use fractal image generator supporting multiple"
                        " views of a four‑dimensional object"),
-            copyright=_("Copyright © 1999-2021, Edwin Young\n"
+            copyright=_("Copyright © 1999-2025, Edwin Young\n"
                         "All rights reserved.\n"
                         "Distributed under the BSD license."
                         ' See the file "LICENSE" for details.'),

manual/content/_index.md

@@ -761,7 +761,7 @@ Gnofract 4D from https://github.com/fract4d/gnofract4d
 
 ## Credits and copyright
 
-Gnofract 4D is Copyright 1999-2020 Edwin Young
+Gnofract 4D is Copyright 1999-2025 Edwin Young
 [[email protected]](mailto:[email protected])
 , and is distributed under the **BSD
 license**.  See the file "LICENSE" for details.