Add support for the Hanifi Rohingya script (bug#55745)
* lisp/language/misc-lang.el ("Hanifi Rohingya"):
New language environment.
Add composition rules for Hanifi Rohingya.
Add sample text and input method.
* lisp/international/fontset.el (script-representative-chars)
(setup-default-fontset): Support Hanifi Rohingya.
* lisp/leim/quail/misc-lang.el ("hanifi-rohingya"):
New input method.
* etc/HELLO: Add a Hanifi Rohingya greeting.
* etc/NEWS: Announce the new language environment.