Use munit diff logic

[zainab-ali]

As part of #15 , we wish to improve the diff rendering of the Comparison trait by using a Myers diff implementation. munit's Myers diff algorithm is a prime candidate.

As discussed on Discord, we prefer to vendor the diff logic than pull in an external dependency.

This PR is an experiment in vendoring.

Note that:

• [x] tests must be updated.
• [x] the scala-diff library is yet to be published.

[zainab-ali]

To summarize the discussions on this, there are two approaches we could take to improving the diff logic:

• Vendor the munit diff code, as is done in the current changeset.
• Pull in the munit-diff library dependency.

I'm exploring pulling in the library dependency, but shading it such that users of weaver and munit are unaffected. Given that the lib is unlikely to change, but is on the same release cadence as munit, releases will also be excluded from Scala Steward.

[Baccata]

Changes look good 👍

Do you have a rough idea of when munit-diff could be released ?

[zainab-ali]

Thanks! The PR has no obvious outstanding issues, so I expect it to be merged in the next few days. I'm not sure of the munit release cycle - @tgodzik may be able to comment.

[tgodzik]

Thanks! The PR has no obvious outstanding issues, so I expect it to be merged in the next few days. I'm not sure of the munit release cycle - @tgodzik may be able to comment.

We plan to do munit 1.0.0-RC1 after that is merged and if nothing pops up later on, we'll release a full 1.0.0

[tgodzik]

Munit and munit-diff 1.0.0-RC1 is out. I also released manually for 0.4 Scala Native. Do let me know if it works!

[Baccata]

Merging even if it depends on an RC, because it's shaded anyway, and because there's still a little bit of work to be done before an actual release of weaver, which may give munit enough time for a 1.0.0 release