RFR: 8311593: Minor doc issue in MemorySegment::copy

[Maurizio Cimadamore]

This simple PR fixes an issue where `this segment` was used in the javadoc of two static methods.

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Commit messages:
 - Initial push

Changes: https://git.openjdk.org/jdk/pull/14813/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14813&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8311593
  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/14813.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14813/head:pull/14813

PR: https://git.openjdk.org/jdk/pull/14813