RemoveUnused.params on Scala 3

scala/scala3#20894

Author: bjaglin

docs/rules/RemoveUnused.md

@@ -90,7 +90,7 @@ On Scala 2.13.15+, canonical patterns (vars with the same names as the
 attributes) do not trigger unused warnings, so the input above will not
 be rewritten. See https://github.com/scala/bug/issues/13035.
 
-### Remove unused function parameters (Scala 2 only)
+### Remove unused function parameters
 
 ```scala
 // before

scalafix-tests/input/src/main/scala-2/test/removeUnused/RemoveUnusedParams.scala renamed to scalafix-tests/input/src/main/scala/test/removeUnused/RemoveUnusedParams.scala

@@ -3,8 +3,6 @@ rule = RemoveUnused
  */
 package test.removeUnused
 
-// Not available as of Scala 3.4.1
-// https://github.com/scalacenter/scalafix/issues/1937
 object UnusedParams {
   val f: String => Unit = unused => println("f")
   val ff = (unused: String) => println("f")

scalafix-tests/output/src/main/scala-2/test/removeUnused/RemoveUnusedParams.scala renamed to scalafix-tests/output/src/main/scala/test/removeUnused/RemoveUnusedParams.scala

@@ -1,7 +1,5 @@
 package test.removeUnused
 
-// Not available as of Scala 3.4.1
-// https://github.com/scalacenter/scalafix/issues/1937
 object UnusedParams {
   val f: String => Unit = _ => println("f")
   val ff = (_: String) => println("f")