Provide some context with rate-limited event

[levenleven]

Currently it is sometimes challenging to debug rate-limited events and handle them in single place, especially when multiple APIs calls are being done simultaneously. The only provided parameter is retrySec:

node-slack-sdk/packages/web-api/src/WebClient.ts

Line 566 in 765743e

this.emit(WebClientEvent.RATE_LIMITED, retrySec);

Would be much more convenient if it would include api endpoint and parameters (e.g. channel in case of chat.postMessage)

Packages:

Select all that apply:

• @slack/web-api
• @slack/rtm-api
• @slack/webhooks
• @slack/oauth
• @slack/socket-mode
• @slack/types
• I don't know

Requirements

Please read the Contributing guidelines and Code of Conduct before creating this issue or pull request. By submitting, you are agreeing to those rules.

[filmaj]

Thanks for filing this and sending a PR implementing this! This is now live in v6.9.0 on npm.