Document the bug report policy

Summary

Location of documentation issue: Nowhere in particular

Write a brief description of the issue.

From our prioritization document:

Some users don't feel that they can report bugs when they are incapable of producing a minimal failing example.

This came from users who experienced bugs that only occurred on large codebases that began failing between releases. They were incapable of producing anything smaller that exhibited the bug, but did not feel like they could report the bug without a reasonbly sized reproduction.

Proposed improvements or changes

Feel free to propose changes, either concrete or abstract.

It should be written somewhere easy to find while reporting bugs that, while small reproductions make it much easier to find and fix the bug, large reproductions are acceptable if they cannot be made smaller, so long as the reproduction codebase is open source.

Environment

• GHC version used (if appropriate):