Enable addtional linters (#34085)

enable mirror, usestdlibbars and perfsprint 
part of: https://github.com/go-gitea/gitea/issues/34083

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

routers/web/org/setting.go

@@ -170,7 +170,7 @@ func SettingsDelete(ctx *context.Context) {
 	ctx.Data["PageIsOrgSettings"] = true
 	ctx.Data["PageIsSettingsDelete"] = true
 
-	if ctx.Req.Method == "POST" {
+	if ctx.Req.Method == http.MethodPost {
 		if ctx.Org.Organization.Name != ctx.FormString("org_name") {
 			ctx.Data["Err_OrgName"] = true
 			ctx.RenderWithErr(ctx.Tr("form.enterred_invalid_org_name"), tplSettingsDelete, nil)