RFR: JDK-8297959: Provide better descriptions for some Operating System JFR events [v3]

[Matthias Baesken]

> Some Operating System JFR events currently lack descriptions , this could be improved.
> See for example https://sap.github.io/SapMachine/jfrevents/20.html#osinformation

Matthias Baesken has updated the pull request incrementally with one additional commit since the last revision:

  small description adjustments

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/11478/files
  - new: https://git.openjdk.org/jdk/pull/11478/files/8b1994a8..869831dd

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=11478&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=11478&range=01-02

  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/11478.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11478/head:pull/11478

PR: https://git.openjdk.org/jdk/pull/11478