Make static xUnit tests instance methods

Proprietary

Remove static from [Fact] and [Theory] methods and from the classes that declare them, since TUnit runs each test on an instance of its class.

OpenRewrite.Recipes.CSharp.Migration.TUnit.FromXUnit.RemoveStaticFromTests

mod run . --recipe=OpenRewrite.Recipes.CSharp.Migration.TUnit.FromXUnit.RemoveStaticFromTests

Install it once, then run it on every repository under the current directory. New to the Moderne CLI? Set it up.