Make it so that mypy thinks that `ParticleLike` has the same attributes as `Particle`

In functions decorated with @particle_input, arguments are converted from something ParticleLike into a Particle | CustomParticle | ParticleList. When an attribute of the processed argument is used, mypy detects a union-attr error, such as in plasmapy.particles.atomic. If we made mypy and static type checkers interpret that ParticleLike had appropriate attributes, then we could avoid these mypy errors. All this applies to ParticleListLike too.

The possibilities that I can think of that might work are:

• Create a .pyi type stub file that overrides ParticleLike
• Add an if typing.TYPE_CHECKING block that adds the attributes to ParticleLike
• Actually add attributes to ParticleLike (though this doesn't seem like a clean way to go about it).

This probably requires some thought, and a better understanding of static type checking in Python. In the meantime, we should add type: ignore[union-attr] comments when this happens. (We probably don't want to disable union-attr checks entirely because they've helped me identify potential bugs.)

Start with the particle_input usage in plasmapy/particles/atomic.py around line 84 and trace the definitions of ParticleLike and ParticleListLike. Compare a stub, TYPE_CHECKING attributes, and runtime attributes while preserving useful union-attr checks. Done means mypy can access the appropriate Particle attributes without unnecessary ignores, with the affected checks passing.