Add tests for Scala 3 macros

[Flowdalic]

This adds a few simple and short tests for the Scala 3 macros. Especially for the central deconstructMessageFormat() macro, which was previously broken and fixed with 66ac4a7 ("Fixed Scala 3 macros (#26)").

[Flowdalic]

@vy In #26 @pjfanning asked for tests for the macros. Here are the tests that I used to debug and fix the macros. Nothing fancy, but I figured I try to contribute before those tests are lost.

[vy]

@Flowdalic, thanks so much! Would you mind fixing the compilation errors, please?

[Flowdalic]

@Flowdalic, thanks so much! Would you mind fixing the compilation errors, please?

Sure. Couldn't figure out that I need ./mvnw test -pl log4j-api-scala_3 to run just the Scala 3 tests. Should compile now :)

[vy]

@Flowdalic, I also need your commits to be signed to be able to merge this PR.

I appreciate it if you can sign the commits. This will give you the full credit in the git log. Otherwise, I can apply your changes myself, I will appear as the committer – though I will link to this issue, where those who are curious can trace back to you.

[Flowdalic]

I appreciate it if you can sign the commits.

Done.

[vy]

@Flowdalic, I think you did a git commit -s. You should rather have done git commit -S. Could you try that and -f push again?

[Flowdalic]

@Flowdalic, I think you did a git commit -s. You should rather have done git commit -S. Could you try that and -f push again?

Oh, you really asked for an OpenPGP signed commit. Not just a signed off trailer. Done.