Add init-only properties to rule

[gewarren]

Fixes #24971

[tdykstra]

LGTM, aside from snippets 5000 warning SYSLIB0003: 'SecurityPermissionAttribute' is obsolete

[BillWagner]

@gewarren @tdykstra The snippets 5000 should allow warnings.

I think the issue is this error:

D:\a\docs\docs\docs\fundamentals\code-analysis\quality-rules\snippets\csharp\all-rules\ca2208.cs(11,23): error CA2208: Method .ctor passes parameter name 'title' as the message argument to a ArgumentNullException constructor. Replace this argument with a descriptive message and pass the parameter name in the correct position. 

[gewarren]

I'm fixing up the warnings/errors in #25046.