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`.

(cherry picked from commit 74f0c84fa4245a20ce6fb87dac1faf2aeeded2a2)

Conflicts:
	.golangci.yml
	apply the linter recommendations to Forgejo code as well

services/webhook/discord.go

@@ -304,14 +304,12 @@ func (discordHandler) NewRequest(ctx context.Context, w *webhook_model.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")
 	}

services/webhook/matrix.go

@@ -217,7 +217,6 @@ func (m matrixConvertor) Push(p *api.PushPayload) (MatrixPayload, error) {
 		if i < len(p.Commits)-1 {
 			text += "<br>"
 		}
-
 	}
 
 	return m.newPayload(text, p.Commits...)