main/mdadm: use lsblk to detect mountpoints
'+' fix alints
lsblk can handle complex setups, like using lvm on luks on mdraid
For example this:
└─nvme1n1p2 259:5 0 884.8G 0 part
└─md1 9:1 0 884.7G 0 raid1
└─crypt-thread 253:0 0 884.7G 0 crypt
├─lvm--thread-swap 253:1 0 64G 0 lvm [SWAP]
└─lvm--thread-root 253:2 0 656.5G 0 lvm /
Edited by Jean-Louis Fuchs