Pass through query type overrides in query chaining, so you don't have to include the computed type in the last function in the chain

**Do you want to request a *feature* or report a *bug*?**

**What is the current behaviour?**
Types do not take account of the type passed to populate.
**If the current behavior is a bug, please provide the steps to reproduce.**

```ts

const trip = await this.ds.model
.findOne(
{
_id: { $in: data.trips },
},
{
carrier: 1,
driver: 1,
},
)
.populate<{ driver: Pick }>('driver', 'name')
.lean<
Pick<
BookingTrip,
| 'carrier'
| '_id'
| 'driver'
>
>();

trip.driver // (property) driver?: string | Driver but it should be (property) driver: Pick
```

```json
{
"compilerOptions": {
"module": "commonjs",
"declaration": true,
"removeComments": true,
"emitDecoratorMetadata": true,
"experimentalDecorators": true,
"allowSyntheticDefaultImports": true,
"target": "es2017",
"sourceMap": true,
"outDir": "./dist",
"baseUrl": "./",
"noEmitOnError": true,
"incremental": true,
"skipLibCheck": true,
"strictNullChecks": false,
"noImplicitAny": false,
"strictBindCallApply": false,
"forceConsistentCasingInFileNames": false,
"noFallthroughCasesInSwitch": false,
"resolveJsonModule": true
}
}
```
**What is the expected behaviour?**
trip.driver should have the correct type `driver: Pick`

**What are the versions of Node.js, Mongoose and MongoDB you are using? Note that "latest" is not a version.**
6.3.1

Start with the TypeScript typings involved in the findOne().populate().lean() query chain, using the supplied reproduction to inspect how the populate generic is carried into lean(). Done means trip.driver is inferred as Pick rather than string | Driver.

Written by the indexing model from the issue text.