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/matrix.go

@@ -179,7 +179,6 @@ func (m matrixConvertor) Push(p *api.PushPayload) (MatrixPayload, error) {
 		if i < len(p.Commits)-1 {
 			text += "<br>"
 		}
-
 	}
 
 	return m.newPayload(text, p.Commits...)