qapi/string-output-visitor: fix human output

"0x1-0x10" looks better than "0x1-10"

Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>

qapi/string-output-visitor.c

@@ -98,7 +98,7 @@ static void format_string(StringOutputVisitor *sov, Range *r, bool next,
 {
     if (r->end - r->begin > 1) {
         if (human) {
-            g_string_append_printf(sov->string, "0x%" PRIx64 "-%" PRIx64,
+            g_string_append_printf(sov->string, "0x%" PRIx64 "-0x%" PRIx64,
                                    r->begin, r->end - 1);
 
         } else {