[foreign-memaccess] RFR: 8247924: Improve javadoc of Foreign Memory Access API (part one) [v2]

[Maurizio Cimadamore]

> This patch clarifies the role of `MemorySegment::close`, and also mentions the fact that external memory sources
> (arrays/buffers) can be aliased, and that extra care must be taken by clients wanting to share such segments.
> I also fixed the typos in restricted methods which we also fixed in foreign-abi.

Maurizio Cimadamore has updated the pull request incrementally with one additional commit since the last revision:

  Update src/jdk.incubator.foreign/share/classes/jdk/incubator/foreign/MemorySegment.java
  
  Co-authored-by: Jorn Vernee <JornVernee at users.noreply.github.com>

-------------

Changes:
  - all: https://git.openjdk.java.net/panama-foreign/pull/209/files
  - new: https://git.openjdk.java.net/panama-foreign/pull/209/files/4392f3c0..bc5309a8

Webrevs:
 - full: https://webrevs.openjdk.java.net/panama-foreign/209/webrev.01
 - incr: https://webrevs.openjdk.java.net/panama-foreign/209/webrev.00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/panama-foreign/pull/209.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-foreign pull/209/head:pull/209

PR: https://git.openjdk.java.net/panama-foreign/pull/209