tmt link doesn't work well

[skycastlelily]

Try to add link by running:
tmt link names beaker --link https://issues.redhat.com 
nothing happens.
It looks like there is at least one issue:
1.we need to change this line to
for link in links.get("relates"):
because links are tmt.base.Links whose default relation is "relates"
2.After I made that change, and run the command,it looks like work well,but after I look into my plan,I found the comment in
the plan is removed:

summary: Basic smoke test
provision:
    how: beaker
    kickstart:
        script: |
            lang en_US.UTF-8
            zerombr
            clearpart --all --initlabel
            part /boot --fstype="ext4" --size=200
            part / --fstype="btrfs" --size=10000 --grow
        metadata:
            # we need this
            no_autopart
execute:
  - script: touch /tmp/lili

vs

summary: Basic smoke test
provision:
    how: beaker
    kickstart:
        script: |
            lang en_US.UTF-8
            zerombr
            clearpart --all --initlabel
            part /boot --fstype="ext4" --size=200
            part / --fstype="btrfs" --size=10000 --grow
        metadata: no_autopart
execute:
  - script: touch /tmp/lili
link:
  - relates: https://issues.redhat.com

I'm not sure this is wanted behavior,IMO,it is very common that we leave some comments in testcases, for others' convenience,
and we may also forget why a specific line is needed.

Just to be clear, this issue has nothing to do with #3339
It's just that I found this while testing that mr, and fvagner-config behaves the same(last run, link) as main branch,just as its comment claims:)