RFR: 8355223: Improve documentation on @IntrinsicCandidate

[Chen Liang]

In offline discussion, we noted that the documentation on this annotation does not recommend minimizing the intrinsified section and moving whatever can be done in Java to Java; thus I prepared this documentation update, to shrink a "TLDR" essay to something concise for readers, such as pointing to that list at `vmIntrinsics.hpp` instead of "a list".

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Commit messages:
 - 8355223: Improve documentation on @IntrinsicCandidate

Changes: https://git.openjdk.org/jdk/pull/24777/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24777&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8355223
  Stats: 91 lines in 1 file changed: 4 ins; 65 del; 22 mod
  Patch: https://git.openjdk.org/jdk/pull/24777.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24777/head:pull/24777

PR: https://git.openjdk.org/jdk/pull/24777