Update related_website_sets.JSON

[miranas-readwhere]

Added RWS entry of sortd.mobi and rwadx.com

[google-cla]

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

View this failed invocation of the CLA check for more information.

For the most up to date status, view the checks section at the bottom of the pull request.

[sjledoux]

Hi, just to clarify the failure here: the issue is that your set submission is missing an additional closing brace - "}" - after the rationaleBySite field.

[github-actions]

It appears you have failed some tests. Here are your results:
There was an error when loading pull-request/related_website_sets.JSON;
error was: Expecting ',' delimiter: line 548 column 3 (char 22212)