GitLab

* README:
* configure.ac:
* nt/README.W32:
* msdos/sed2v2.inp:
* src/msdos.c (internal_terminal_init):
* etc/refcards/ru-refcard.tex: Bump Emacs version to 28.0.50.

* lisp/cus-edit.el (customize-changed-options-previous-release):
Bump up the value to 26.3.

* etc/NEWS.27: Renamed from NEWS.
* etc/NEWS: New file for Emacs 28.