RFR: 8309981: Remove expired flags in JDK 23

[David Holmes]

All expired flags are removed from the flags table.

The two documented flags have their documentation moved from the obsolete section to the removed section.

The link to JDK 22 removed flags is added to the list.

Thanks.

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Commit messages:
 - Revert "8322065: Initial nroff manpage generation for JDK 23"
 - Revert "Revert "8309981: Remove expired flags in JDK 23""
 - Revert "8309981: Remove expired flags in JDK 23"
 - 8322065: Initial nroff manpage generation for JDK 23
 - 8309981: Remove expired flags in JDK 23

Changes: https://git.openjdk.org/jdk/pull/17107/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17107&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8309981
  Stats: 23 lines in 2 files changed: 11 ins; 10 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/17107.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17107/head:pull/17107

PR: https://git.openjdk.org/jdk/pull/17107