docs: add performance to readme

Author: anonrig

README.md

@@ -24,4 +24,23 @@ fn main() {
     u.set_port("9999");
     println!("href: {:?}", u.href());
 }
+```
+
+### Performance
+
+Ada is fast. The benchmark below shows **2 times** faster URL parsing compared to `url`
+
+```
+     Running bench/parse.rs (target/release/deps/parse-dff65469468a2cec)
+url_parse/ada_parse     time:   [2.5853 µs 2.5982 µs 2.6115 µs]
+                        change: [-3.8745% -2.9874% -2.0620%] (p = 0.00 < 0.05)
+                        Performance has improved.
+Found 2 outliers among 100 measurements (2.00%)
+  1 (1.00%) low mild
+  1 (1.00%) high severe
+url_parse/servo_parse   time:   [5.5127 µs 5.6287 µs 5.8046 µs]
+                        change: [+0.7618% +3.0977% +6.5694%] (p = 0.01 < 0.05)
+                        Change within noise threshold.
+Found 2 outliers among 100 measurements (2.00%)
+  2 (2.00%) high severe
 ```