Mismatch type for predicate failures

[aniketd]

Description

This is the first part of #4619. After this the priority is to first get Conway predicates to use the new Mismatch type, and then the rest of the remaining eras.

Checklist

• Commit sequence broadly makes sense and commits have useful messages
• New tests are added if needed and existing tests are updated
• All visible changes are prepended to the latest section of a CHANGELOG.md for the affected packages.
  New section is never added with the code changes. (See RELEASING.md)
• When applicable, versions are updated in .cabal and CHANGELOG.md files according to the
  versioning process.
• The version bounds in .cabal files for all affected packages are updated.
  If you change the bounds in a cabal file, that package itself must have a version increase. (See RELEASING.md)
• Code is formatted with fourmolu (use scripts/fourmolize.sh)
• Cabal files are formatted (use scripts/cabal-format.sh)
• hie.yaml has been updated (use scripts/gen-hie.sh)
• Self-reviewed the diff

[lehins]

This looks great!

@aniketd I'll review it again once you address all the comments, but you can already start on integrating Mismatch into Conway predicate failures using this PR

[lehins]

Looking much better, but there is still one small mistake.

[lehins]

Looks great. Thank you!