RFR: 8356632: Fix remaining {@link/@linkplain} tags with refer to private/protected types in java.base

[Nizar Benalla]

Please review this patch to fix some `javadoc` bugs in `java.base`.
Certain `@link` tags used to refer to private fields instead of public APIs.

A couple of `@see` tags in the [serialization page](https://download.java.net/java/early_access/jdk25/docs/api/serialized-form.html#java.lang.invoke.MethodType) referred to private methods, I updated the javadoc in a way to not change the way it is displayed to users but also remove `@link` tags to non-included types.

TIA

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Commit messages:
 - respond to feedback
 - fix incorrect `@link` tags

Changes: https://git.openjdk.org/jdk/pull/25287/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=25287&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8356632
  Stats: 14 lines in 6 files changed: 0 ins; 0 del; 14 mod
  Patch: https://git.openjdk.org/jdk/pull/25287.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25287/head:pull/25287

PR: https://git.openjdk.org/jdk/pull/25287