Examples/Details for interfaces of HasCheckConstraint

These two seem strait forward. the second string is just the SQL that represents the constraint.

* HasCheckConstraint(EntityTypeBuilder, String, String)
* HasCheckConstraint<TEntity>(EntityTypeBuilder<TEntity>, String, String)

Q) Are there any limitations to a constraint applied in this way? Are there any limitations based on the Database Target? Such as MySQL vs MSSql.

This DataAnnotation version however, raises a few questions.

* HasCheckConstraint(IConventionEntityTypeBuilder, String, String, Boolean)

1) Which DataAnnotations are supported? Any? Or is there a set of DataAnnotations that are explicitly supported? What about custom DataAnnotations?
2) Are there DataAnnotations that are not supported when using a specific Database Target? MySQL vs MSSql?

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* ID: 1bb554ee-fe06-b145-318a-735b1d5f3495
* Version Independent ID: f9bd034e-3c22-c710-80ed-e3f4d1acaac1
* Content: [RelationalEntityTypeBuilderExtensions.HasCheckConstraint Method (Microsoft.EntityFrameworkCore)](https://docs.microsoft.com/en-us/dotnet/api/microsoft.entityframeworkcore.relationalentitytypebuilderextensions.hascheckconstraint?view=efcore-3.0#Microsoft_EntityFrameworkCore_RelationalEntityTypeBuilderExtensions_HasCheckConstraint_Microsoft_EntityFrameworkCore_Metadata_Builders_EntityTypeBuilder_System_String_System_String_)
* Content Source: [dotnet/xml/Microsoft.EntityFrameworkCore/RelationalEntityTypeBuilderExtensions.xml](https://github.com/aspnet/EntityFramework.ApiDocs/blob/live/dotnet/xml/Microsoft.EntityFrameworkCore/RelationalEntityTypeBuilderExtensions.xml)
* Product: **ef-core-api**
* GitHub Login: @dotnet-bot
* Microsoft Alias: **divega**