RFR: 8370154: Update @jls and @jvms taglets to point to local specs dir [v3]

[Chen Liang]

On Tue, 11 Nov 2025 00:36:30 GMT, Dan Smith <dlsmith at openjdk.org> wrote:

>> Updated the JSpec taglets to use relative links into `../specs/jls` and `../specs/jvms` rather than external links, possible now due to JDK-8370153.
>> 
>> I was surprised there doesn't seem to be a standard way to get a relative path to the docs root, but I copy/pasted from ToolGuide, and made some tweaks based on failures I saw.
>> 
>> Tested with 'make docs' and manually confirmed that a handful of different `@jls` and `@jvms` tags are pointing to the right place.
>
> Dan Smith has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Comment about open-source builds

Marked as reviewed by liach (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/28207#pullrequestreview-3446476869