Add toggle-window-dedicated command and mode-line-window-dedicated

Add toggle-window-dedicated command and mode-line-window-dedicated

It's sometimes useful to interactively make certain windows dedicated.
This allows a level of interactive control over which window
display-buffer uses.

Additionally, when a window is dedicated (even without this new
command) it can affect display-buffer behavior in ways which may be
unexpected for users.  Let's display the window dedicated status in
the mode-line to help indicate what's going on.

* doc/emacs/windows.texi (Displaying Buffers): Add information about
dedicated windows and toggle-window-dedicated.
* doc/emacs/screen.texi (Mode Line): Add information about the window
dedicated indicator.
* etc/NEWS: Announce mode-line-window-dedicated and
toggle-window-dedicated.
* lisp/window.el (toggle-window-dedicated): Add.  (bug#64619)
(window-prefix-map): Add C-x w d binding.
* lisp/bindings.el (mode-line-window-control): Add.
(mode-line-window-dedicated): Add.
(standard-mode-line-format): Insert mode-line-window-dedicated.