Webhooks API isn't complete.

[FedorLap2006]

When I was reading the Discord API docs as usual... while making #933 I found that our current API is missing the one endpoint. And these endpoints: webhook execute, webhook message edit and message delete lack support of attachments. And in case of webhook message edit endpoint - it's also missing returned by the endpoint message object (updated message).

P.S. Basically I have the code to fix these issue, but would like to know, open another PR on that, or include it straight into #933?

[FedorLap2006]

Since no one wants to respond, I will probably include them in the next PR.

[jolheiser]

I would argue that webhook changes should go in a separate PR unless they are added specifically for the interactions.

e.g. attachment support could probably go in another PR

[FedorLap2006]

Well, late. Already pushed this to #954. Can remove the code from there tho