RFR: 8370800: Downgrade cant.attach.type.annotations diagnostics to warnings [v5]

[Liam Miller-Cushon]

> Hi, please consider this fix for [JDK-8370800: Downgrade cant.attach.type.annotations diagnostics to warnings](https://bugs.openjdk.org/browse/JDK-8370800).
> 
> As discussed in the, this reduces the compatibility impact of these diagnostics for builds that deliberately omit transitive annotation dependencies, for example if they are only referenced through javadoc `@link` tags, or by frameworks that conditionally load the classes.
> 
> The PR changes the existing error diagnostic to an unconditional warning. Another alternative would be to make it an optional xlint diagnostic, perhaps as part of `-Xlint:classfile`, or as another category.

Liam Miller-Cushon has updated the pull request incrementally with one additional commit since the last revision:

  Chain completers

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Changes:
  - all: https://git.openjdk.org/jdk/pull/28018/files
  - new: https://git.openjdk.org/jdk/pull/28018/files/2781df57..d78c3425

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=28018&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=28018&range=03-04

  Stats: 23 lines in 1 file changed: 0 ins; 18 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/28018.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28018/head:pull/28018

PR: https://git.openjdk.org/jdk/pull/28018