Rename repo_model.SearchOrderByMap to repo_model.OrderByMap (#31359)

https://github.com/go-gitea/gitea/pull/30876#discussion_r1637112394

routers/api/v1/repo/repo.go

@@ -184,7 +184,7 @@ func Search(ctx *context.APIContext) {
 		if len(sortOrder) == 0 {
 			sortOrder = "asc"
 		}
-		if searchModeMap, ok := repo_model.SearchOrderByMap[sortOrder]; ok {
+		if searchModeMap, ok := repo_model.OrderByMap[sortOrder]; ok {
 			if orderBy, ok := searchModeMap[sortMode]; ok {
 				opts.OrderBy = orderBy
 			} else {