Add user option to enable Doxygen syntax highlighting (bug#72814)

Add user option to enable Doxygen syntax highlighting (bug#72814)

Both 'c-ts-mode' and 'java-ts-mode' have a new user option,
'c-ts-mode-enable-doxygen' and 'java-ts-mode-enable-doxygen'
(defaults to nil) which allow to enable syntax highlighting
of comment blocks based on the Doxygen grammar.

* lisp/progmodes/c-ts-mode.el: Add the 'c-ts-mode-enable-doxygen'
user option variable to disable doxygen grammar.
Notifies the user if doxygen grammar is not available.
* lisp/progmodes/c-ts-mode.el (c-ts-mode, c++-ts-mode): Use the
new 'c-ts-mode-enable-doxygen' option.
* lisp/progmodes/java-ts-mode.el: Add the
'java-ts-mode-enable-doxygen' user option variable to disable
doxygen grammar.  Notifies the user if doxygen grammar is not
available.
* lisp/progmodes/java-ts-mode.el (java-ts-mode): Use the new
'java-ts-mode-enable-doxygen' option.

* etc/NEWS: Document the change.

(cherry picked from commit b0523dffabbec8acd9c5c92711af849a11867884)