[foreign-jextract] RFR: Refresh docs to reflect Java 18 API changes [v2]

[Maurizio Cimadamore]

> This patch updates the memory access and linker docs to reflect the Java 18 API changes.

Maurizio Cimadamore has updated the pull request incrementally with eight additional commits since the last revision:

 - Update doc/panama_memaccess.md
   
   Co-authored-by: Jorn Vernee <JornVernee at users.noreply.github.com>
 - Update doc/panama_ffi.md
   
   Co-authored-by: Jorn Vernee <JornVernee at users.noreply.github.com>
 - Update doc/panama_memaccess.md
   
   Co-authored-by: Jorn Vernee <JornVernee at users.noreply.github.com>
 - Update doc/panama_ffi.md
   
   Co-authored-by: Jorn Vernee <JornVernee at users.noreply.github.com>
 - Update doc/panama_ffi.md
   
   Co-authored-by: Jorn Vernee <JornVernee at users.noreply.github.com>
 - Update doc/panama_ffi.md
   
   Co-authored-by: Jorn Vernee <JornVernee at users.noreply.github.com>
 - Update doc/panama_ffi.md
   
   Co-authored-by: Jorn Vernee <JornVernee at users.noreply.github.com>
 - Update doc/panama_ffi.md
   
   Co-authored-by: Jorn Vernee <JornVernee at users.noreply.github.com>

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

Changes:
  - all: https://git.openjdk.java.net/panama-foreign/pull/630/files
  - new: https://git.openjdk.java.net/panama-foreign/pull/630/files/eda8a689..94fdabc1

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=panama-foreign&pr=630&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=panama-foreign&pr=630&range=00-01

  Stats: 8 lines in 2 files changed: 0 ins; 0 del; 8 mod
  Patch: https://git.openjdk.java.net/panama-foreign/pull/630.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-foreign pull/630/head:pull/630

PR: https://git.openjdk.java.net/panama-foreign/pull/630