Make experimental final

Author: noti0na1

library/src-bootstrapped/scala/annotation/experimental.scala

@@ -5,6 +5,5 @@ package scala.annotation
  *  @see [[https://dotty.epfl.ch/docs/reference/other-new-features/experimental-defs]]
  *  @syntax markdown
  */
-@deprecatedInheritance("Scheduled for being final in the future", "3.4.0")
-class experimental(message: String) extends StaticAnnotation:
+final class experimental(message: String) extends StaticAnnotation:
   def this() = this("")

library/src-non-bootstrapped/scala/annotation/experimental.scala

@@ -1,4 +1,3 @@
 package scala.annotation
 
-@deprecatedInheritance("Scheduled for being final in the future", "3.4.0")
-class experimental extends StaticAnnotation
+final class experimental extends StaticAnnotation

project/MiMaFilters.scala

@@ -9,6 +9,7 @@ object MiMaFilters {
       // Additions that require a new minor version of the library
       Build.mimaPreviousDottyVersion -> Seq(
         ProblemFilters.exclude[DirectMissingMethodProblem]("scala.annotation.experimental.this"),
+        ProblemFilters.exclude[FinalClassProblem]("scala.annotation.experimental"),
       ),
 
       // Additions since last LTS

tests/neg/experimentalExperimental.scala

@@ -0,0 +1 @@
+class MyExperimentalAnnot extends scala.annotation.experimental // error