chore: Rename encoder to strategy/swap_encoder

This was confusing me when I had all of them open at the same time. Better to be extra explicit

--- don't change below this line ---
ENG-4081 Took 2 minutes

src/encoding/evm/swap_encoder/builder.rs

@@ -1,5 +1,5 @@
 use crate::encoding::{
-    evm::swap_encoder::encoders::{BalancerV2SwapEncoder, UniswapV2SwapEncoder},
+    evm::swap_encoder::swap_encoders::{BalancerV2SwapEncoder, UniswapV2SwapEncoder},
     swap_encoder::SwapEncoder,
 };
 

src/encoding/evm/swap_encoder/mod.rs

@@ -1,6 +1,6 @@
 mod builder;
-mod encoders;
 mod registry;
+mod swap_encoders;
 
 use std::sync::RwLock;