add jspecify NonNull annotation to NotNullAnnots list

[Cherry-picked 9da102b]

Author: matsu-chara

compiler/src/dotty/tools/dotc/core/Definitions.scala

@@ -1087,7 +1087,8 @@ class Definitions {
     "lombok.NonNull" ::
     "reactor.util.annotation.NonNull" ::
     "reactor.util.annotation.NonNullApi" ::
-    "io.reactivex.annotations.NonNull" :: Nil)
+    "io.reactivex.annotations.NonNull" ::
+    "org.jspecify.annotations.NonNull" :: Nil)
 
   // convenient one-parameter method types
   def methOfAny(tp: Type): MethodType = MethodType(List(AnyType), tp)