Replace byebug with debug for debugging

[larouxn]

What are you trying to accomplish?

Replace the use of byebug (plus irb and reline) with debug for debugging.

• https://github.com/deivid-rodriguez/byebug
• https://github.com/ruby/debug

Follow up to/requires

• Bump minitest from 5.17.0 to 5.27.0 #362
• Add support for and start testing against Ruby 4 #434

What approach did you choose and why?

Cleaner, simpler, and more modern.

What should reviewers focus on?

Any reason we want to stick with byebug?

The impact of these changes

More standard Ruby codebase.

Testing

Testing debugging works while working on fixing these tests.

Checklist

• I have added a CHANGELOG entry for this change (or determined that it isn't needed)

Determined not necessary as it's a developer facing change, not user facing.

[afurm]

Is the ostruct dependency actually required here? The debug gem's declared dependencies are irb and reline, neither of which appear to need ostruct directly — it's typically pulled in by irb for things like IRB::Irb#suspend (which uses OpenStruct for context). If ostruct is only needed transitively through irb, it should already be satisfied. Could this be an over-declaration?

[larouxn]

👋 @afurm, that addition of ostruct was actually done in #434 which is my PR that adds Ruby 4 support to this gem. This PR is branched off of that PR and one prior to that which bumps minitest gem to latest.

As for whether ostruct is a required dependency I'm simply going off of the behaviour when running tests. It appears that as Ruby 4 (originally 3.5) made ostruct optional, everything blows up without it required.