Merge pull request #417 from SethTisue/make-nowarn-support-2.12.13

Author: SethTisue

compat/src/main/scala-2.11_2.12/scala/annotation/nowarn.scala

@@ -12,11 +12,11 @@
 
 package scala.annotation
 
-/** An annotation for local warning suppression added in 2.13.2. Note that this annotation has
- * no functionality when used in Scala 2.11 or 2.12, but allows cross-compiling code that uses
- * `@nowarn`.
+/** An annotation for local warning suppression added in 2.13.2 and 2.12.13. Note that this
+ * annotation has no functionality when used in Scala 2.11, but allows cross-compiling code
+ * that uses `@nowarn`.
  *
  * For documentation on how to use the annotation in 2.13 see
  * https://www.scala-lang.org/api/current/scala/annotation/nowarn.html
  */
-class nowarn(value: String = "") extends StaticAnnotation
+class nowarn(value: String = "") extends ClassfileAnnotation