add diffy, prettydiff

prettydiff/src/main.rs

@@ -0,0 +1,15 @@
+use prettydiff::diff_slice;
+
+// https://github.com/romankoblov/prettydiff
+fn main() {
+  println!("Diff: {}", diff_slice(&[1, 2, 3, 4, 5, 6], &[2, 3, 5, 7]));
+  println!(
+      "Diff: {}",
+      diff_slice(&["q", "a", "b", "x", "c", "d"], &["a", "b", "y", "c", "d", "f"])
+  );
+  println!(
+      "Diff: {}",
+      diff_slice(&["a", "c", "d", "b"], &["a", "e", "b"])
+  );
+}
+