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/strategy_encoder/mod.rs

@@ -1,2 +1,2 @@
-mod encoder;
-mod selector;
+mod strategy_encoders;
+mod strategy_selector;

src/encoding/evm/strategy_encoder/strategy_selector.rs

@@ -2,7 +2,9 @@ use tycho_core::models::Chain;
 
 use crate::encoding::{
     errors::EncodingError,
-    evm::strategy_encoder::encoder::{SplitSwapStrategyEncoder, StraightToPoolStrategyEncoder},
+    evm::strategy_encoder::strategy_encoders::{
+        SplitSwapStrategyEncoder, StraightToPoolStrategyEncoder,
+    },
     models::Solution,
     strategy_encoder::{StrategyEncoder, StrategySelector},
 };