Clarify C# 9 / C# 10 differences

[CalvinAllen]

The article starts out with a call to C# 9, but I found the switch to C# 10 features to be very easy to miss. I made an original assumption that in C# 9, record / record class / record struct, were all introduced at the same time. I also don't see clarification that a record struct is a "value type". Since record is called out in the beginning as a "reference type", I began to assume that a record struct was as well. In between the C# 9 and C# 10 section (mostly at the top, by the way), it's called out that a record uses "value equality" (while also mentioning "reference type" again), but it's never mentioned that a record struct ALSO uses value equality. Maybe some of that assumes underlying knowledge of a struct, since its the same, but I think it would be good to call it out explicitly since record class called it out.

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• ID: 20818c64-4ad8-fb15-5d79-e7f98614e9c4
• Version Independent ID: de1f383b-ef20-4776-57a8-04edae892166
• Content: Records - C# reference
• Content Source: docs/csharp/language-reference/builtin-types/record.md
• Product: dotnet-csharp
• Technology: csharp-language-reference
• GitHub Login: @BillWagner
• Microsoft Alias: wiwagn

[BillWagner]

Thanks @CalvinAllen

I've added this to the current sprint.

From our offline conversation, the main concerns are to distinguish record, record class and record struct. C# 9 added record types (which are classes). C# 10 added record struct types, and allowed record class types to clarify that a record is a class type.