Add clarification about generalizable structures

I think this page is missing a clarification about generalizable structures, for instance why is it possible to define an option or list of generic values but not an array, a seq, map or dictionary of them ie: why `[id;id]` alone is a valid expression but not `[| id;id |]`.

It seems this dates back to F# 2 https://stackoverflow.com/a/2758456/446822

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#### Document Details

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* ID: 85b50526-a200-3774-0f70-d1079d783d9c
* Version Independent ID: e6f2ac27-6633-b9f9-6739-f48aef5595ad
* Content: [Automatic Generalization - F#](https://docs.microsoft.com/en-us/dotnet/fsharp/language-reference/generics/automatic-generalization)
* Content Source: [docs/fsharp/language-reference/generics/automatic-generalization.md](https://github.com/dotnet/docs/blob/main/docs/fsharp/language-reference/generics/automatic-generalization.md)
* Product: **dotnet-fsharp**
* GitHub Login: @cartermp
* Microsoft Alias: **phcart**