- Create optional with ~ instead of ?. return io::EOF?; becomes return io::EOF~.

- Deprecated use of `?` to create optional.

test/test_suite/errors/more_optional_tests.c3

@@ -4,10 +4,10 @@ faultdef ABC;
 
 fn void test()
 {
-	int x = ABC? ?? 123;
+	int x = ABC~ ?? 123;
 }
 
 fn void test2()
 {
-	int? y = ABC? ?? ABC?;
+	int? y = ABC~ ?? ABC~;
 }