Let /duplicate mark issues as related

Problem

When issues are marked as duplicates, it is sometimes difficult to go back later to easily reference comments the wider community has made across a series of issues that all are working towards the same goal.

Proposal

When issues are marked as a duplicate, automatically relate the issue being marked with the issue that is the canonical issue source.

Success Criteria

Completion Criteria

• When an issue is marked as a duplicate of another, the two issues are automatically related.
• Documentation

Documentation

• I'm assuming so!