Extract types into a separate module

src/types/side.rs

@@ -0,0 +1,22 @@
+use std::fmt::Display;
+
+#[cfg(feature = "serde")]
+use serde::{Deserialize, Serialize};
+
+/// Pretty-printable flag to tell which conflicting edit (side)
+/// an operation is associated with.
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum Side {
+    Left,
+    Right,
+}
+
+impl Display for Side {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Side::Left => write!(f, "Left"),
+            Side::Right => write!(f, "Right"),
+        }
+    }
+}