Make default formatter include more details about version being reported

[mgorny]

Say:

dev-python/selenium
  PythonCompatUpdate: version 4.26.1: PYTHON_COMPAT update available: python3_14
  PythonCompatUpdate: version 4.31.0: PYTHON_COMPAT update available: python3_14
  RedundantVersion: version 4.32.0: slot(0) keywords are overshadowed by version: 4.33.0-r1
  LaggingStable: version 4.33.0-r1: slot(0), stabled arches: [ amd64, arm, arm64, ppc ], lagging: [ ~ppc64, ~sparc, ~x86 ]

I would find it helpful if it included some more details about these versions, like "[l]" for "latest", or "[s]" for stable.