add SQLOFunc type and update SQLO error messages

dbxm/mysql.go

@@ -32,7 +32,7 @@ var (
 
 // SQLO returns the current SQL database handle.
 func SQLO() *sql.DB {
-	dbModule.RequireLoaded("dbx.SQLO requires database module") // ensure the module is loaded before accessing the database
+	dbModule.RequireLoaded("dbxm.SQLO requires database module") // ensure the module is loaded before accessing the database
 	if sqlDB == nil {
 		panic("SQL database not initialized")
 	}