Feature idea: all classes must be marked as `partial`

[Aaronontheweb]

In order to make our software open for extension, without the use of evil extension methods, we need to make sure we're using the partial keyword everywhere just in case we want the option to modify them.

[TenCoKaciStromy]

Not just classes, but other types too!

[Tornhoof]

Funny Thing, in modern c# they tend to be partial because of source Generators.