Related merge requests shouldn't be part of the body of the issue
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### Description
It's nice that we list related merge requests at the bottom of an issue.
However, as it's visually part of the issue, it's not clear whether it's been added manually or if it's an automatic system that puts them there.

### Proposal
* Separate somehow the related merge requests from the body of the issue
### Links / references
Example: https://gitlab.com/gitlab-org/gitlab-ce/issues/19797
cc @awhildy
issue