2.28.5 (stable) 2026-05-26

Documentation:
* Don't link to removed parts of gnome.org
* Replace gtkmm.org by gtkmm.gnome.org
* Remove obsolete FSF (Free Software Foundation) address
* codegen/extradefs/generate_extra_defs_atk.cc: The license is
  GNU General Public License, version 2, as said in COPYING.tools.
  (Kjell Ahlstedt)
* README.win32.md: Mention Visual Studio 2026
* Visual Studio builds: Update build information
  (Chun-wei Fan) Merge request !11

Meson build:
* Require python3 >= 3.7. That's what Meson requires.
* Require meson >= 0.60.0.
* subprojects/atk.wrap points at at-spi2-core.
  GNOME/atk moved to GNOME/at-spi2-core long ago
* Use the Python installation that Meson uses.
  See merge request glibmm!67
  (Kjell Ahlstedt)
* Meson and NMake builds: Distinguish Visual Studio 2026 builds
  from Visual Studio 2022 builds
* NMake Makefiles: Consolidate items and improve flexibility
* NMake Makefiles: Make build process more robust
  (Chun-wei Fan) Merge request !11
* NMake Makefiles: Update .m4 installation
  (Chun-wei Fan) Merge request !13
* Don't require the 'dot' command to build the documentation
  (Kjell Ahlstedt)