Added an example that shows how similar performs for large diffs

Cargo.toml

@@ -61,5 +61,9 @@ required-features = ["text", "bytes"]
 name = "close-matches"
 required-features = ["text"]
 
+[[example]]
+name = "large"
+required-features = ["text"]
+
 [profile.release]
 debug = true

examples/large.rs

@@ -0,0 +1,8 @@
+use similar::TextDiff;
+
+fn main() {
+    let x = "abc".repeat(2000);
+    let y = "abd".repeat(2000);
+    let diff = TextDiff::from_chars(&x, &y);
+    println!("{}", diff.unified_diff());
+}