Fixing errors in SortedDictionary<TKey,TValue>.IDictionary.Keys Property page

https://docs.microsoft.com/en-us/dotnet/api/system.collections.generic.sorteddictionary-2.system-collections-idictionary-keys?view=net-5.0#System_Collections_Generic_SortedDictionary_2_System_Collections_IDictionary_Keys

This weblink contains weird empty blocks. Seems like someone forgot to delete this.


Corresponding sample file refers to
```

//
}
}
//

```
from https://github.com/dotnet/dotnet-api-docs/blob/main/samples/snippets/csharp/VS_Snippets_CLR/Generic.SortedDictionary.IDictionary/CS/source.cs

https://github.com/dotnet/dotnet-api-docs/blob/main/samples/snippets/visualbasic/VS_Snippets_CLR/Generic.SortedDictionary.IDictionary/VB/source.vb