Modify man page of "--pids-limit" option to correct a default value.
Correct the documented default number of pids limit from 4096 to 2048.
####> are applicable to all of those.
#### **--pids-limit**=*limit*
-Tune the container's pids limit. Set to **-1** to have unlimited pids for the container. The default is **4096** on systems that support "pids" cgroup controller.
+Tune the container's pids limit. Set to **-1** to have unlimited pids for the container. The default is **2048** on systems that support "pids" cgroup controller.
