RFR: 8321561: (fs) Clarify non-atomic behavior of Files.move [v3]

[Brian Burkhalter]

> Make it clear that a `FileAlreadyExistsException` may be thrown by `Files.move` even if the `REPLACE_EXISTING` option is specified.

Brian Burkhalter has updated the pull request incrementally with one additional commit since the last revision:

  8321561: Address Reviewer comments

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Changes:
  - all: https://git.openjdk.org/jdk/pull/17061/files
  - new: https://git.openjdk.org/jdk/pull/17061/files/ee6fbfcb..06732ccb

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=17061&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=17061&range=01-02

  Stats: 9 lines in 1 file changed: 0 ins; 1 del; 8 mod
  Patch: https://git.openjdk.org/jdk/pull/17061.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17061/head:pull/17061

PR: https://git.openjdk.org/jdk/pull/17061