distinguish between W+ and W- in particle type#288

BrianMarre wants to merge 1 commit intoopenPMD:upcoming-2.0.0openPMD/openPMD-standard:upcoming-2.0.0from

BrianMarre:topic-fixW-BosonParticleTypeBrianMarre/openPMD-standard:topic-fixW-BosonParticleTypeCopy head branch name to clipboard