Update NotifyCollectionChangedAction enum "Reset" description to not let it look like clearing collection

[marcelwgn]

Currently, the description of the "Reset" value on the NotifyCollectionChangedAction enum page indicates that the collection was cleared. However some collection (for example Platform::Collections::Vector) use the reset event do indicate that the collection went through dramatic changes, such as ReplaceAll.

The UWP documentation for the enum describe the "Reset" value better:

The content of the collection changed dramatically.

In order for the value to be understand correctly, I think the documentations should line up regarding on what this value should or is used for.

See this issue over at WinUI for more context.

[mairaw]

Thanks for your feedback @chingucoding. Would you like to submit a PR to fix this?
Here's some info about that: https://docs.microsoft.com/en-us/contribute/#quick-edits-to-existing-documents

[mairaw]

I also noticed that this would match what's in the source code: https://source.dot.net/#System.ObjectModel/System/Collections/Specialized/NotifyCollectionChangedAction.cs,33

[GF-Huang]

So how can I access the OldItems when I got a Reset which casued by .Clear()?