added information regarding documentation with new separate repository mathjax-docs and readthedocs service

Release-process-checklist.md

@@ -3,6 +3,7 @@
 1. All code changes are internally tested according to the MathJax [[Development Process]], and merged into the `mathajx/master` branch at GitHub. Repack and recombine the files to make sure they are consistent with the unpacked versions.
 2. If this is a numbered release, the `vN.M-latest` branch is created, and a README-branch.txt file is made for the version number, and committed to the branch.  This makes the branch appear as a separate line in the network viewer.
 3. The release is tagged in GitHub.  This causes a labeled distribution to be created (with the tag name) in the GitHub download manager.
+3. Repeat both steps for `mathjax-docs`.
 4. The download distribution should then be downloaded and smoke tested.
 
 ### At CDN
@@ -13,12 +14,13 @@
 ### At mathjax.org
 
 1. The download page should be updated to point to the new release.
-3. Update the documentation.
 2. A news announcement for the release is posted.  The post should
     * Describe what is new
     * Point to the release
     * Give instructions for reporting bugs, and refer questions to MathJax Users
 
+Note: with switch to readthedocs, updating the documentation is automatic.
+
 ### For the community
 
 * Announcement should be posted to the User Groups at mathjax-dev and mathjax-users