<i18n dev> RFR: JDK-8305206: Add @spec tags in java.base/java.* (part 1)

[Jonathan Gibbons]

Please review a change to add `@spec` tags (and remove some equivalent `@see` tags) to the main "core-libs" packages in `java.base` module.

This is similar to, and a subset of, PR #11073.   That PR was withdrawn, and based on the ensuing discussion and suggestion, is now being handled with a series of PRs for various separate parts of the system.  Follow-up PRs will be provided for the rest of `java.base`, for `java.desktop`, and for XML APIs.  The "LangTools" modules have already been updated.  The "External Specifications" page has been temporarily [disabled][] until this work is complete.

While the primary content of the change was automated, I've manually adjusted the formatting, to break long lines.

It is clear there is significant inconsistency in the ordering of block tags in doc comment.   We might want to (separately) consider normalizing the order of the tags, perhaps according to the order defined for the tags in the generated output, as given [here][]

[here]: https://github.com/openjdk/jdk/blob/83cf28f99639d80e62c4031c4c9752460de5f36c/make/Docs.gmk#L68
[disabled]: https://github.com/openjdk/jdk/blob/83cf28f99639d80e62c4031c4c9752460de5f36c/make/Docs.gmk#L115

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Commit messages:
 - JDK-8305206: Add @spec tags in java.base/java.* (part 1)

Changes: https://git.openjdk.org/jdk/pull/13248/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13248&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8305206
  Stats: 281 lines in 60 files changed: 267 ins; 14 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/13248.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13248/head:pull/13248

PR: https://git.openjdk.org/jdk/pull/13248