Constrain ECS type to EcdsaChannelSigner.

Author: arik-so

lightning/src/sign/type_resolver.rs

@@ -1,11 +1,11 @@
-use crate::sign::ChannelSigner;
+use crate::sign::{ChannelSigner, EcdsaChannelSigner};
 
 pub(crate) enum ChannelSignerType<ECS: ChannelSigner> {
 	// in practice, this will only ever be an EcdsaChannelSigner (specifically, Writeable)
 	Ecdsa(ECS)
 }
 
-impl<ECS: ChannelSigner> ChannelSignerType<ECS>{
+impl<ECS: EcdsaChannelSigner> ChannelSignerType<ECS>{
 	pub(crate) fn as_ref(&self) -> &dyn ChannelSigner {
 		match self {
 			ChannelSignerType::Ecdsa(ecs) => ecs