//! Optimizer index-hint AST leaf (ADR 0053, RQL Phase 2 S4b).
//!
//! [`IndexHint`] is referenced by the canonical SQL AST
//! (`ExpandOptions.index_hint`). Only the hint *data* lives here; the optimizer
//! passes that build it stay in the server planner
//! (`storage::query::planner::optimizer`), which keeps a re-export shim.
/// Hint about which index method to prefer for a query
/// Which index method the optimizer recommends