Documentation for OrderedDictionary<TKey,TValue>

### Describe the issue or suggestion

The documentation for [`OrderedDictionary`](https://learn.microsoft.com/en-us/dotnet/api/system.collections.generic.ordereddictionary-2?view=net-9.0) does not include any information about how it differs from using a `Dictionary`. The summary of "Represents a collection of key/value pairs that are accessible by the key or index." suggests that you can access elements in their added order but to do so requires casting to `IList` which isn't obvious.