asPromise should be mentioned in error handling documentation

[auctormaximus]

Prerequisites

• I have written a descriptive issue title
• I have searched existing issues to ensure the feature has not already been requested

🚀 Feature Proposal

asPromise should be mentioned and given an example for in Connection. We are now told to use .catch and await for error handling but this can't be done for createConnection without asPromise which is not mentioned anywhere. There lacks an explanation how to do error handling for createConnection.

Motivation

It took several hours of work just to make simple error handling for createConnection because of the lack of this critical information and because error handling is a basic feature it should not be hidden away in docs/api

Example

Add a line like below or at least mention the need of asPromise in text.

try {
  await mongoose.createConnection('mongodb://127.0.0.1:27017/test').asPromise();
} catch (error) {
  handleError(error);
}