[buffer] fix duplicate assert and comment
this originates from for no apparent reason
@@ -131,10 +131,8 @@ char* buffer_string_prepare_append(buffer *b, size_t size) {
if (buffer_string_is_empty(b)) {
return buffer_string_prepare_copy(b, size);
} else {
- size_t req_size = b->used + size;
-
/* not empty, b->used already includes a terminating 0 */
- force_assert(req_size >= b->used);
+ size_t req_size = b->used + size;
/* check for overflow: unsigned overflow is defined to wrap around */
force_assert(req_size >= b->used);
