- Auto-register func Type_Method(self: T, ...) as methods in sema.
- Add method table lookup for binary operators in sema.bux ekBinary.
- Add method table lookup for operator_index_get in sema.bux ekIndex.
- Add HIR lowering for binary operators to method calls in hir_lower.bux.
- Add HIR lowering for operator_index_get/set in hir_lower.bux.
- Set expr.refType for overloaded operators so chained ops work.