Convert Twig engine hooks

Changes are made on on 11.x (our main development branch) first, and are then back ported as needed according to our policies.

Oh, thanks.
I'm postponing that on 📌 [Plan] Determine how to deprecate procedural hooks. Active

These aren't real hooks anyway, they are invoked individually for the theme engine. 📌 Convert theme engines into services Needs work would likely remove them all and convert them to methods on service classes.

Yeah I found these recently, but the Registry needs work to convert theme or theme engine hooks.

I'll follow that other issue too, I hadn't seen it.

Yes, 📌 Convert theme engines into services Needs work makes sense.
I'm closing the duplicated issue