[Feature Request] Add rerolled winners to giveaway embed

[MertBhey]

Giveaway summary and the giveaway message is not updating when the giveaway is rerolled.

[jagrosh]

The giveaway summary cannot be edited once it exists, as it is a static file.

Adding rerolled winners to the original embed is feasible.

[jagrosh]

Just realized this is a duplicate of #156