options: do not spew out the help text when an option is not recognized

When getopt() does not recognize an option, it returns '?', which means
that '-?' cannot be used as a valid option because any invalid option
would be treated the same way as '-?'.

Spewing out the full help text drowns the "invalid option" message at
the beginning.

This fixes https://savannah.gnu.org/bugs/?59530.

Bug existed since version 5.3, commit 5bd92d4c.

src/nano.c

@@ -1848,7 +1848,7 @@ int main(int argc, char **argv)
 		SET(RESTRICTED);
 
 	while ((optchr = getopt_long(argc, argv, "ABC:DEFGHIJ:KLMNOPQ:RST:UVWX:Y:Z"
-				"abcdef:ghijklmno:pqr:s:tuvwxyz$?%!", long_options, NULL)) != -1) {
+				"abcdef:ghijklmno:pqr:s:tuvwxyz$%!", long_options, NULL)) != -1) {
 		switch (optchr) {
 #ifndef NANO_TINY
 			case 'A':
@@ -2001,7 +2001,6 @@ int main(int argc, char **argv)
 				break;
 #endif
 			case 'h':
-			case '?':
 				usage();
 				exit(0);
 #ifndef NANO_TINY