changelog doesn't contain Scala 3

[He-Pin]

https://www.scala-lang.org/download/changelog.html
Only Scala 2.13.x and previous

[SethTisue]

We should kill that page, I think, as it has just turned into links to release notes, and we don't need to keep the historical information around.

Also, there is an effort underway within the Scala org to produce a Scala 3 doc page that shows the status of all recent language features: when they were introduced as experimental and when they became final (if they have), that kind of thing. That will serve the same purpose.

[SethTisue]

PR: #1765