Function run_callers 

pub fn run_callers(
    target: &str,
    scope: &Path,
    expand: usize,
    budget_tokens: Option<u64>,
    limit: Option<usize>,
    offset: usize,
    glob: Option<&str>,
    cache: &OutlineCache,
    depth: Option<usize>,
    max_frontier: Option<usize>,
    max_edges: Option<usize>,
    skip_hubs: Option<&str>,
    json: bool,
) -> Result<String, SrcwalkError>

Find all callers of a symbol.