Organizing the NEWS file a bit better

[Stefan Kangas]

I'm looking at re-organizing NEWS a bit, and I'm not sure how we prefer it.

In general, I guess I also wonder if anyone will protest if I take it
upon myself to move things around to more sensible places.

Here are some concrete questions:

- Under "Changes in Specialized Modes and Packages" things seem thrown
  in more or less at random.  Do we prefer to order it according to
  perceived order of importance?  Would it make sense to organize it
  alphabetically?

- Does "Tab Bars" belong under "Changes in Emacs" rather than
  "Specialized Modes"?  It's more like a core feature to my mind, even
  if not everyone uses it.  (I've moved "Windows" and "Frames" there
  already.)

- Under "Incompatible Editing Changes" we have several items relating
  to specialized modes (f90-mode, nroff-mode, vc, project).  Do these
  entries belong under "Specialized Modes and Packages"?

- Could we just put new headers for macOS and MS-Windows under "Emacs
  28.1 on Non-Free Operating Systems"?  Entries now start with "On
  macOS ..." or "On MS-Windows ...", which we could avoid.

- Under "Editing Changes" we have many things that doesn't seem like
  they belong there.  Should they be moved?  See the list below where
  I've marked things that we might want to move with "x".

  * Editing Changes in Emacs 28.1
x ** New value 'save-some-buffers-root' of
'save-some-buffers-default-predicate'.
x ** Dragging a file to Emacs will now also push the name of the file
  ** Menus
x *** New minor mode 'context-menu-mode' for context menus popped by 'mouse-3'.
  *** The "Edit => Clear" menu item now obeys a rectangular region.
  ** New command 'execute-extended-command-for-buffer'.
  ** New user option 'read-extended-command-predicate'.
x ** 'eval-expression' now no longer signals an error on incomplete expressions.
x ** 'eval-last-sexp' now handles 'defvar'/'defcustom'/'defface' specially.
  ** Standalone 'M-y' allows interactive selection from previous kills.
x ** New user options 'copy-region-blink-delay' and 'delete-pair-blink-delay'.
  ** New command 'undo-redo'.
x ** 'read-number' now has its own history variable.
  ** Input history for 'goto-line' can now be made local to every buffer.
  ** New command 'goto-line-relative' to use in a narrowed buffer.
  ** When called interactively, 'goto-char' now offers the number at
x ** When 'suggest-key-bindings' is non-nil, the completion list of 'M-x'
  ** Autosaving via 'auto-save-visited-mode' can now be inhibited by
x ** New commands to describe buttons and widgets have been added.
x ** Obsolete aliases are no longer hidden from command completion.
  ** New command 'revert-buffer-with-fine-grain'.
  ** New command 'memory-report'.
  ** New user option 'isearch-repeat-on-direction-change'.
  ** New commands 'copy-matching-lines' and 'kill-matching-lines'.
  ** Setting 'fill-column' to nil is obsolete.