add IncludeMany exception tips

FreeSql/Internal/CommonProvider/SelectProvider/Select1Provider.cs

@@ -372,6 +372,7 @@ namespace FreeSql.Internal.CommonProvider
             if (whereExp == null)
             {
                 tbref = tb.GetTableRef(collMem.Member.Name, true);
+                if (tbref == null) throw new Exception($"IncludeMany 类型 {tb.Type.DisplayCsharp()} 的属性 {collMem.Member.Name} 不是有效的导航属性，提示：IsIgnore = true 不会成为导航属性");
             }
             else
             {