Function annotation_reference_candidates_at_focus 

pub fn annotation_reference_candidates_at_focus(
    graph: &PythonGraphSource<'_>,
    python: &dyn PythonUsageSource,
    file: &ProjectFile,
    source: &str,
    node: Node<'_>,
    focus_start: usize,
    focus_end: usize,
    target_self_file: bool,
) -> Option<Vec<CodeUnit>>

Resolve only the annotation identifier selected by one definition request. Quoted annotations are reparsed with original byte coordinates, while the original syntax node remains the lexical class-scope anchor.