Code completion for the field-reference argument of the javadoc {@value} tag

### Description

Provide code completion for the _field-reference_ argument of the javadoc `{@value}` tag (see [value](https://docs.oracle.com/en/java/javase/21/docs/specs/javadoc/doc-comment-spec.html#value)). This would work in a similar fashion to the code completion for arguments to javadoc tags like `{@link}`.

### Use case/motivation

_No response_

### Related issues

_No response_

### Are you willing to submit a pull request?

No

Start by locating the existing code-completion implementation for arguments to the javadoc {@link} tag, then compare it with handling of {@value}'s field-reference argument. Use the Java SE 21 {@value} specification as the behavior reference. Done means valid field references receive completion suggestions in {@value} tags, with coverage for the new completion behavior.

Written by the indexing model from the issue text.