Report if a package is a reproducible build or is just semantically equivalent

The oss-reproducible measures if a regenerated package is "semantically equivalent" to the posted package. One thing it tries to do is determine if a build is a "reproducible build", that is, if it's bit-for-bit identical. Being a reproducible build is the best possible evidence of something being semantically equivalent!! It'd be awesome if the tool could report if a package is a reproducible build when it is, instead of only reporting that it's semantically equivalent (without adding that additional information when it's true).

It shouldn't be too hard to make the report, you're already doing the hard part :-). But this is more than a documentation change, and #426 was purely about changing the term to make it clearer to everyone.

If anyone is reading this and wants more context, see:

• Rename "semantically reproducible builds" - #426
• Reproducible-builds mailing list thread
• SLSA issue #873

Thanks so much!

The issue names no files, tests, or entry points; start by tracing where OSSGadget currently produces the semantically equivalent report and review #426 for terminology context. Done means the report explicitly identifies packages that are bit-for-bit reproducible while preserving the existing semantic-equivalence result for other cases.