fix memory stats display document
@@ -2343,7 +2343,7 @@ Running `docker stats` on multiple containers
$ docker stats redis1 redis2
CONTAINER CPU % MEM USAGE/LIMIT MEM % NET I/O
- redis1 0.07% 796 KiB/64 MiB 1.21% 788 B/648 B
+ redis1 0.07% 796 KB/64 MB 1.21% 788 B/648 B
redis2 0.07% 2.746 MB/64 MB 4.29% 1.266 KB/648 B
