Generic IEnumerator not disposed

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I'm using Mapster.Tool to generate extension methods from my mapping registrations like so:

```csharp
config.NewConfig().GenerateMapper(MapType.Map | MapType.MapToTarget);
```

When inspecting the generated code I noticed that anywhere GetEnumerator() is used, the generic Enumerator is never disposed.

This is a snippet of what is being generated:

```csharp
...
IEnumerator enumerator = p2.GetEnumerator();

while (enumerator.MoveNext())
{
string item = enumerator.Current;
result.Add(item);
}

return result;
```

I believe what it should be generating is the following:

```csharp
using IEnumerator enumerator = p2.GetEnumerator();

while (enumerator.MoveNext())
{
string item = enumerator.Current;
result.Add(item);
}

return result;
```

I'm not sure if this issue arises in other areas (e.g. generated code from interfaces) as I haven't tested it personally, but I would expect the Mapster.Tool generates the code the same way.

Start with Mapster.Tool and reproduce the generated extension method using the shown NewConfig().GenerateMapper(...) registration. Inspect the GetEnumerator() generation path, including generated code from interfaces if applicable; done means generated generic enumerators are disposed while iteration behavior remains unchanged.

Written by the indexing model from the issue text.