RFR: 8340307: Add explanation around MemorySegment:reinterpret regarding arenas [v4]

[Per Minborg]

> This PR proposes to add a small text segment on the `MemorySegment::reinterpret` overloads that takes an Arena stating the responsibility of actually freeing reinterpreted segments lies with the *original* arena.

Per Minborg has updated the pull request incrementally with one additional commit since the last revision:

  Improve docs

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Changes:
  - all: https://git.openjdk.org/jdk/pull/21761/files
  - new: https://git.openjdk.org/jdk/pull/21761/files/0ab8ec11..34e5b122

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=21761&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21761&range=02-03

  Stats: 4 lines in 1 file changed: 0 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/21761.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21761/head:pull/21761

PR: https://git.openjdk.org/jdk/pull/21761