RFR: 5705: Explain metaspace in rule results

[Suchita Chaturvedi]

This enhancement updates MetaspaceOomRule and IncreasingMetaspaceLiveSetRule with the proper explanation and relevant real time values which were missing.

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Commit messages:
 - 5705: Explain metaspace in rule results

Changes: https://git.openjdk.org/jmc/pull/654/files
  Webrev: https://webrevs.openjdk.org/?repo=jmc&pr=654&range=00
  Issue: https://bugs.openjdk.org/browse/JMC-5705
  Stats: 44 lines in 6 files changed: 18 ins; 1 del; 25 mod
  Patch: https://git.openjdk.org/jmc/pull/654.diff
  Fetch: git fetch https://git.openjdk.org/jmc.git pull/654/head:pull/654

PR: https://git.openjdk.org/jmc/pull/654