[FEATURE]: Prepared Statement: expected placeholder typings

### Feature hasn't been suggested before.

- [x] I have verified this feature I'm about to request hasn't been suggested before.

### Describe the enhancement you want to request

After creating a prepared statement, it doesn't seem to get the types for the `.execute()` part.

Not sure if possible or how hard, so the suggestion would be to add a generic to prepare:

```ts
const prepared = db.query.table.findMany({
where: (t, f) => f.eq(t.id, sql.placeholder('id'))
}).prepare<{ id: number }>()
```

This way should be more feasible to pull those types and have intellisense on `.execute()`.