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`.

routers/api/v1/repo/issue.go

@@ -217,7 +217,6 @@ func SearchIssues(ctx *context.APIContext) {
 
 	var includedAnyLabels []int64
 	{
-
 		labels := ctx.FormTrim("labels")
 		var includedLabelNames []string
 		if len(labels) > 0 {