Missing documentation on args for entire list changed (-1, -1)

The `ListChangedEventArgs` is documented to also be used for if not only specific items changed, but also if the entire list changed. It does not however say how this is declared.

It looks like the framework implements `OldIndex = -1` and `NewIndex = -1` as the arguments for the entire list changed.

[`DataView` for example defines a `ResetEventArgs` field with such a value.](https://referencesource.microsoft.com/#System.Data/System/Data/DataView.cs,580db5e53398e044,references)

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* ID: 97c8c9f6-72f6-2fb9-feed-d9a0bfb6348f
* Version Independent ID: 72c6439d-375b-e584-fd70-593411554e41
* Content: [ListChangedEventArgs Class (System.ComponentModel)](https://docs.microsoft.com/en-us/dotnet/api/system.componentmodel.listchangedeventargs?view=netframework-4.7.2)
* Content Source: [xml/System.ComponentModel/ListChangedEventArgs.xml](https://github.com/dotnet/dotnet-api-docs/blob/master/xml/System.ComponentModel/ListChangedEventArgs.xml)
* Product: **dotnet-api**
* GitHub Login: @dotnet-bot
* Microsoft Alias: **dotnetcontent**