RFR: 8376274: JSpec preview support and output enhancement [v3]

[Chen Liang]

> We can enhance the `@jls` and `@jvms` tags in-place to support preview JLS/JVMS, such as in this PR:
> 
> 
> @jls primitive-types-in-patterns-instanceof-switch-5.7.1 Exact Testing Conversions
> 
> 
> Taglet now parses "primitive-types-in-patterns-instanceof-switch-" preview and links to `primitive-types-in-patterns-instanceof-switch-jls.html` where the 5.7.1 anchor exists.
> 
> As a side effect, I adjusted the output to remove the preview prefix, and discovered we can embellish the output more, in particular, including a section sign for inline tags and including a trailing dot for block tags.
> 
> I need this feature in project Valhalla, where there are JLS and JVMS for value-objects and strict-fields that we need to link to. Please help review!

Chen Liang has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains four additional commits since the last revision:

 - Add preview superscript when applicable
 - Merge branch 'master' of https://github.com/openjdk/jdk into feature/jspec-enhance
 - Remove redundant dot
 - 8376274: JSpec preview support and output enhancement

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/29402/files
  - new: https://git.openjdk.org/jdk/pull/29402/files/74af3243..1e414f9f

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=29402&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=29402&range=01-02

  Stats: 3783 lines in 168 files changed: 1984 ins; 859 del; 940 mod
  Patch: https://git.openjdk.org/jdk/pull/29402.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29402/head:pull/29402

PR: https://git.openjdk.org/jdk/pull/29402