Further adjustments for restoring killed buffer windows (Bug#68235)

Further adjustments for restoring killed buffer windows (Bug#68235)

* etc/NEWS: Announce 'window-restore-killed-buffer-windows'.
* src/buffer.h (struct buffer) : New field last_name_.
* src/buffer.c (Fbuffer_last_name): New function to return last
name of buffer before it was killed or renamed.
(bset_last_name, Fget_buffer_create, Fmake_indirect_buffer)
(Frename_buffer, Fkill_buffer, init_buffer_once): Set buffer's
last_name_ field accordingly.
* src/window.c (window_restore_killed_buffer_windows): New
variable replacing Vwindow_kept_windows_functions.
(Fset_window_configuration): Use
window_restore_killed_buffer_windows instead of
Vwindow_kept_windows_functions.
* lisp/window.el (window--state-put-2, window-state-put): Use
'window-restore-killed-buffer-windows' instead of
'window-kept-windows-functions'.
* doc/lispref/windows.texi (Window Configurations): Describe
'window-restore-killed-buffer-windows' which replaces
'window-kept-windows-functions'.