update how to publish, doc index

PUBLISH.md

@@ -71,8 +71,7 @@ openpgp-revocs.d  pubring.asc        trustdb.gpg
 1. Build and test locally.
 
 2. Bump `lazy val Version` in `build.sbt`, run `package` in sbt. Note no plus before package as from 1.2.0 we only publish for Scala 3. We also want a release on github and the course home page aligned with the release on Sonatype Central. Therefore You should also:
-  - Don't forget to update the `rootdoc.txt` file with current version information and package contents etc.: https://github.com/lunduniversity/introprog-scalalib/blob/master/src/rootdoc.txt
-  TODO: Update this to scaladoc 3 which use markdown and other things instead of rootdoc.txt see furter here: https://docs.scala-lang.org/scala3/scaladoc.html
+  - Don't forget to update the `doc/index.md` file with current version information and package contents etc. Read more on scaladoc here: https://docs.scala-lang.org/scala3/scaladoc.html
   - commit all changes and push and *then* create a github release with the packaged jar uploaded to https://github.com/lunduniversity/introprog-scalalib/releases
   - Publish the jar to the course home page at http://cs.lth.se/lib using  `sh publish-jar.sh`
   - Publish updated docs to the course home page at http://cs.lth.se/api using script `sh publish-doc.sh`