Update AtlasHepMC

In this MR:

• make HepMC::suggest_barcode() return bool instead of being void.
• Fix formatting running astyle Generators/AtlasHepMC/AtlasHepMC/*h --keep-one-line-blocks --keep-one-line-statements -A2

mentioned in merge request !38880 (merged)

This merge request affects 1 package:

• Generators/AtlasHepMC

This merge request affects 9 files:

• Generators/AtlasHepMC/AtlasHepMC/Flow.h
• Generators/AtlasHepMC/AtlasHepMC/GenEvent.h
• Generators/AtlasHepMC/AtlasHepMC/GenParticle.h
• Generators/AtlasHepMC/AtlasHepMC/GenVertex.h
• Generators/AtlasHepMC/AtlasHepMC/HEPEVT_Wrapper.h
• Generators/AtlasHepMC/AtlasHepMC/IO_GenEvent.h
• Generators/AtlasHepMC/AtlasHepMC/PdfInfo.h
• Generators/AtlasHepMC/AtlasHepMC/Polarization.h
• Generators/AtlasHepMC/AtlasHepMC/SimpleVector.h

added Generators master review-pending-level-1 labels

CI Result SUCCESS (hash 2129c5e6)

	Athena	AthSimulation	AthGeneration	AnalysisBase
externals
cmake
make
required tests
optional tests

Full details available on this CI monitor view
Athena: number of compilation errors 0, warnings 0
AthSimulation: number of compilation errors 0, warnings 0
AthGeneration: number of compilation errors 0, warnings 0
AnalysisBase: number of compilation errors 0, warnings 0
For experts only: Jenkins output [CI-MERGE-REQUEST-CC7 24647]

MR looks good. Approving (L1)

added review-approved label and removed review-pending-level-1 label

merged

mentioned in commit 8246251f

added sweep:ignore label