fix generatetype assembly ref issue

[LumiaSnow]

When I regist interception to the method which have return or parameter of generatetype, for example:

public virtual async Task< Class2 > Invoke(); // Class2 is from another assembly.

I got the error:

Dora.Interception.InterceptionException:“It fails to generate proxy class.
(69,60): error CS0246: 未能找到类型或命名空间名“ClassLibrary1”(是否缺少 using 指令或程序集引用?)
(69,82): error CS0012: 类型“Class2”在未引用的程序集中定义。必须添加对程序集“ClassLibrary1, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null”的引用。
(16,50): error CS0246: 未能找到类型或命名空间名“ClassLibrary1”(是否缺少 using 指令或程序集引用?)
(59,141): error CS0246: 未能找到类型或命名空间名“ClassLibrary1”(是否缺少 using 指令或程序集引用?)
(60,189): error CS0246: 未能找到类型或命名空间名“ClassLibrary1”(是否缺少 using 指令或程序集引用?)
(82,31): error CS0012: 类型“Class2”在未引用的程序集中定义。必须添加对程序集“ClassLibrary1, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null”的引用。
(83,36): error CS0029: 无法将类型“System.Threading.Tasks.Task<ClassLibrary1.Class2>”隐式转换为“System.Threading.Tasks.Task<ClassLibrary1.Class2>””

I found the reason:
The method CodeGenerationContext.References.Add(Assembly assembly) can not add the assemly for the parameter of generatetype.

Fix:
Add a method AddReference, if the type is generatetype, add the assembly recursively.