Plasmapy: Cleanup test_transport.py

[lemmatum]

class Test_classical_transport is in dire need of some error strings which return the compared values when a test fails. Best to do this with f-strings.

[Nismirno]

Hi,
I would like to take up on that issue.

[StanczakDominik]

Hey @Nismirno, thanks for the offer ! Would you mind waiting until #191 is merged into master (likely within ~2 days) to start working on this one? It'd be much easier to work based on a shared history when that one's settled!

If you're okay with that, I'll ping you once that's done!

[Nismirno]

Hi @StanczakDominik,
Sure. I have no problems with that.

[StanczakDominik]

@Nismirno, I'm pinging you as #191 just got merged! :D