[Documentation] System.Security.Permissions.SecurityPermissionAttribute is not in System.Runtime.dll

### Type of issue

Missing information

### Description

Following a linkage issue I had and the documentation, I looked for System.Security.Permissions.SecurityPermissionAttribute in System.Runtime.dll but failed to find it there (as well as in the more expected file System.Security.Permissions.dll).

Based on the position in the repo - https://github.com/dotnet/runtime/blob/5535e31a712343a63f5d7d796cd874e563e5ac14/src/libraries/System.Private.CoreLib/src/System/Security/Permissions/SecurityPermissionAttribute.cs
I looked for it in System.Private.CoreLib.dll, and indeed found it there.

(.NET version is 8).

### Page URL

https://learn.microsoft.com/en-us/dotnet/api/system.security.permissions.securitypermissionattribute?view=net-8.0

### Content source URL

https://github.com/dotnet/dotnet-api-docs/blob/main/xml/System.Security.Permissions/SecurityPermissionAttribute.xml

### Document Version Independent Id

65cc006f-3ba1-e727-afd8-9f88c171df21

### Article author

@dotnet-bot