Enable highlighting Gud execution lines without hl-line-mode

Enable highlighting Gud execution lines without hl-line-mode

* doc/emacs/building.texi (Debugger Operation): Mention two new
options and the relationship between Gud and HL Line Mode.

* etc/NEWS (Editing Changes in Emacs 30.1): Mention the new
option.

* lisp/progmodes/gud.el (gud-highlight-current-line-overlay):
New variable.
(gud-sentinel) <signal, exit>: Delete that overlay if set.
(gud-highlight-current-line, gud-highlight-current-line-face):
New user options.
(gud-display-line): Create and move an overlay without employing
hl-line-mode, if so enjoined by the user.