Make HitInfo and HurtInfo read/init only

[Chicken-Bones]

What is the new feature?

NPC.HitInfo and Player.HurtInfo are now readonly and have get; init properties.

Why should this be part of tModLoader?

I see people trying to do
hit.Crit = false, which compiles but doesn't do anything

Are there alternative designs?

Make the hook parameters in instead. This would be just as breaking, and not carry through to user's own non-hook methods. The dotnet guidelines also recommend making a struct readonly if it's going to be used with in where possible (though this is a performance detail that isn't too relevant to us).

Sample usage for the new feature

ExampleMod updates

None required