fix: Fixed incorrect type definition for Query's .map function

[GCastilho]

Summary

The type definition for the Query.map() function is incorrect. As an example, it does not understand that a Model.find() returns an array nor "pass the mapped value foward" in a correct way

Examples

Old:

Model.find().map(v => v) // v has type `DocType`

New:

Model.find().map(v => v) // v has type `DocType[]`

Old:

Trade.findOne().map(v => v._id).map(w => w) // w has type `DocType`

New:

Trade.findOne().map(v => v._id).map(w => w) // w has type `ObjectId`

[vkarpov15]

Nice, thanks 👍