Make CultureDictionaryRecordKey record struct

[hishamco]

Addresses #11358 (comment)

[sebastienros]

No hashcode, no IEqutable, no constructors ...

Just a ToString() and something like this:

public record struct Person
{
    public required string FirstName { get; init; }
    public required string LastName { get; init; }
};

[sebastienros]

... a record provides the rest automatically

https://sharplab.io/#v2:EYLgtghglgdgNAExAagD4AEBMAGAsAKAPQGYACAJwFMBjAe3IVIGcAXcgV2pdIAVLymtGAQDeBUhNIkKlAI7soVRugCM2UgDFFrAHIQwlUiNIBzSiwDcpWFEukAvuMnSq8xZWVrSAGQi79hsZmdjZ2joT4klJktABu/ORQCIaq6gAqtADKbLAmABQAlE4SYpFRzgDsmtosegYWxQ4E9hZAA=

Select the decompiled version in the drop down

[hishamco]

@sebastienros anything else to add?