Release version 0.6.0

[namurphy]

Following up on the discussion in #895, it'd be good to release version 0.6.0 in March or April. We can use this issue to discuss what we want to make sure gets into this release.

[namurphy]

There are a few things related to plasmapy.particles that I think we ought to get into our next release.

• We updated ParticleLike in Describe valid representations for particles in docstring for ParticleLike typing alias #985 to include a (hopefully) complete description of how particles can be represented in PlasmaPy. We ought to use ParticleLike in docstrings consistently in the formulary and elsewhere to link to that description, especially since particles can be confusing when beginning to use PlasmaPy.
• If we want to use ParticleLike in type hint annotations, we would need to update @particle_input to accept ParticleLike instead of (or in addition to) Particle. Related to: Update @particle_input to handle typing that utilzes Union[], List[], etc. #912, Update @particle_input docstring on use of Optional[Particle] annotations #913.
• Similarly, we should make @particle_input accept CustomParticle instances (Make @particle_input compatible with CustomParticle and ParticleLike #807).
• I'd like to get ParticleList (Create a ParticleCollection class #948, Create custom list for particles #1017) implemented, and make it such that plasmapy.formulary functions can work with lists of particles (i.e., gyroradius(B=..., particle=["p+", "e-"]) would return an array with the gyroradii for protons and electrons). This would also require some changes to @particle_input too.

[StanczakDominik]

Oh wow, you mean you read what's going on in those big PRs? I have to admit I've stopped doing that for PRs I'm not handling, and wanted to discuss this at the telecon today :D but sure...

I'll review the particle list asap!

[StanczakDominik]

You know what we should also do?

• Change the three 2/3 featured notebooks on the main docs index to showcase the newest and coolest functionality

[namurphy]

Change the three featured notebooks on the main docs index to showcase the newest and coolest functionality

Perhaps we could have the first notebook be one for getting started with PlasmaPy, and the other two could be the newest and coolest functionality?

[StanczakDominik]

Quoting myself from chat:

Honestly I dislike the ITER data analysis notebook, it's too basic; can we just replace that with the proton radiography one and keep thomson up? Make this an actual highlight reel and I promise I'll write a proper "start using plasmapy" notebook for 0.7?

This is what pushed through #1065 and what I commit to doing for 0.7. For now, we're on schedule to release tomorrow, so I'll close this one :)