Fix isprintrune()'s behaviour

I somehow missed this issue. A rune can not be smaller than the left
range-delimiter and bigger than the right range-delimiter at the
same time.
The real check has to check if either condition applies.

libutf/isprintrune.c

@@ -6,5 +6,5 @@ int
 isprintrune(Rune r)
 {
 	return !iscntrlrune(r) && (r != 0x2028) && (r != 0x2029) &&
-	       (r < 0xFFF9) && (r > 0xFFFB);
+	       ((r < 0xFFF9) || (r > 0xFFFB));
 }