improvement - Show duplicate mounts

Will it be possible for lfs to highlight duplicated mounts?
```
┌────────────────────────────┬────┬────┬─────┬─────────┬─────┬─────┬──────────────────┐
│ filesystem │type│disk│used │ use │free │size │mount point │
├────────────────────────────┼────┼────┼─────┼─────────┼─────┼─────┼──────────────────┤
│/dev/nvme0n1p2 │xfs │SSD │ 26Gi│26% █▍ │ 74Gi│100Gi│/ │
│/dev/nvme7n1p1 │xfs │SSD │ 17Gi│66% ███▍ │8.4Gi│ 25Gi│/var/Data │
│/dev/mapper/vg1-LVvarStriata│ext4│LVM │ 17Gi│66% ███▍ │8.4Gi│ 25Gi│/var/Data │
│/dev/nvme8n1p1 │xfs │SSD │8.4Gi│56% ██▊ │6.6Gi│ 15Gi│/usr/local/App │
│/dev/nvme4n1p1 │xfs │SSD │216Mi│ 2% ▏ │ 11Gi│ 11Gi│/var/App-local │
│/dev/nvme1n1 │xfs │SSD │1.6Gi│32% █▋ │3.4Gi│5.0Gi│/home │
│/dev/nvme6n1p1 │xfs │SSD │1.0Gi│34% █▊ │2.0Gi│3.0Gi│/var/log │
│/dev/nvme3n1 │xfs │SSD │372Mi│18% ▉ │1.6Gi│2.0Gi│/tmp │
└────────────────────────────┴────┴────┴─────┴─────────┴─────┴─────┴──────────────────┘
```
Somehow the old mount was not removed in the fstab and seems that both were mounted at the same time with the second one taking priority.

Locate the code that gathers mounted filesystems and renders the table; the issue names no file or test. Read those entry points first, then determine how duplicate mount points should be identified and visibly highlighted. Done means simultaneous duplicate mounts are clearly distinguished in the displayed output.

Written by the indexing model from the issue text.