Update intro.md (#17899)

Add additional resource for EF Core keys.

Author: HamidMolareza

aspnetcore/data/ef-rp/intro.md

@@ -154,7 +154,7 @@ A student can enroll in any number of courses, and a course can have any number
 
   [!code-csharp[Main](intro/samples/cu30snapshots/1-intro/Models/Student.cs)]
 
-The `ID` property becomes the primary key column of the database table that corresponds to this class. By default, EF Core interprets a property that's named `ID` or `classnameID` as the primary key. So the alternative automatically recognized name for the `Student` class primary key is `StudentID`.
+The `ID` property becomes the primary key column of the database table that corresponds to this class. By default, EF Core interprets a property that's named `ID` or `classnameID` as the primary key. So the alternative automatically recognized name for the `Student` class primary key is `StudentID`. For more information, see [EF Core - Keys](/ef/core/modeling/keys?tabs=data-annotations).
 
 The `Enrollments` property is a [navigation property](/ef/core/modeling/relationships). Navigation properties hold other entities that are related to this entity. In this case, the `Enrollments` property of a `Student` entity holds all of the `Enrollment` entities that are related to that Student. For example, if a Student row in the database has two related Enrollment rows, the `Enrollments` navigation property contains those two Enrollment entities.