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

modules/process/manager_stacktraces.go

@@ -339,7 +339,6 @@ func (pm *Manager) ProcessStacktraces(flat, noSystem bool) ([]*Process, int, int
 	}
 	sort.Slice(processes, after(processes))
 	if !flat {
-
 		var sortChildren func(process *Process)
 
 		sortChildren = func(process *Process) {