RFR: 8349653: Clarify the docs for MemorySegment::reinterpret

[Per Minborg]

This PR proposes to clarify the documentation for two of the `MemorySegment::reinterpret` overloads.

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Commit messages:
 - Revise MemorySegment::reinterpret docs

Changes: https://git.openjdk.org/jdk/pull/23688/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23688&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8349653
  Stats: 18 lines in 1 file changed: 0 ins; 0 del; 18 mod
  Patch: https://git.openjdk.org/jdk/pull/23688.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23688/head:pull/23688

PR: https://git.openjdk.org/jdk/pull/23688