Enable more revive linter rules (#30608)

Noteable additions:

- `redefines-builtin-id` forbid variable names that shadow go builtins
- `empty-lines` remove unnecessary empty lines that `gofumpt` does not
remove for some reason
- `superfluous-else` eliminate more superfluous `else` branches

Rules are also sorted alphabetically and I cleaned up various parts of
`.golangci.yml`.

services/webhook/discord.go

@@ -274,14 +274,12 @@ func newDiscordRequest(ctx context.Context, w *webhook_model.Webhook, t *webhook
 
 func parseHookPullRequestEventType(event webhook_module.HookEventType) (string, error) {
 	switch event {
-
 	case webhook_module.HookEventPullRequestReviewApproved:
 		return "approved", nil
 	case webhook_module.HookEventPullRequestReviewRejected:
 		return "rejected", nil
 	case webhook_module.HookEventPullRequestReviewComment:
 		return "comment", nil
-
 	default:
 		return "", errors.New("unknown event type")
 	}