servo: Merge #6991 - Add doc.s.o to the readme (from Manishearth:readme-doc); r=Ms2ger

Source-Repo: https://github.com/servo/servo
Source-Revision: 3b4b59551d9e2ba2501f4d991fadeb0215a323a7

servo/README.md

@@ -133,3 +133,6 @@ Use `./mach run [url]` to run Servo.
 
 There are lots of mach commands you can use. You can list them with `./mach
 --help`.
+
+
+The generated documentation can be found on http://doc.servo.org/servo/index.html