Add code of conduct to the README

README.md

@@ -1,19 +1,32 @@
 This repository hosts the [URL Standard](https://url.spec.whatwg.org/).
 
+### Code of conduct
+
+We are committed to providing a friendly, safe and welcoming environment for all. Please read and
+respect the [WHATWG Code of Conduct](https://wiki.whatwg.org/wiki/Code_of_Conduct).
+
+### Contribution opportunities
+
+Folks notice minor and larger issues with the URL Standard all the time and we'd love your help
+fixing those. Pull requests for typographical and grammar errors are also most welcome.
+
+We'd be happy to mentor you through this process. If you're interested and need help getting
+started, leave a comment on the issue or ask around [on IRC](https://wiki.whatwg.org/wiki/IRC).
+
 ### Pull requests
 
-See the [whatwg/html README](https://github.com/whatwg/html/blob/master/README.md) for the general
-guidelines. Note that `source` is `url.bs` and "Acknowledgements" is "Acknowledgments" here (I
-know). Also, the URL Standard uses [bikeshed](https://github.com/tabatkins/bikeshed) to generate
+See the [html repository's README](https://github.com/whatwg/html/blob/master/README.md) for the
+general guidelines. Note that `source` is `url.bs` and "Acknowledgements" is "Acknowledgments" here
+(I know). Also, the URL Standard uses [bikeshed](https://github.com/tabatkins/bikeshed) to generate
 `url.html`. (Do not worry if using that tool is too complicated, your pull request does not need to
 contain the generated HTML.)
 
 ### Merge policy
 
-If you can commit to this repository, see
-[whatwg/html TEAM](https://github.com/whatwg/html/blob/master/TEAM.md) for guidelines.
+If you can commit to this repository, see the
+[html repository's TEAM](https://github.com/whatwg/html/blob/master/TEAM.md) for guidelines.
 
 ### Tests
 
-Tests can be found in the `url/` directory of
-[`w3c/web-platform-tests`](https://github.com/w3c/web-platform-tests).
+Tests can be found in the `url/` directory of the
+[web-platform-tests repository](https://github.com/w3c/web-platform-tests).