default -> companion: replace all mentions of default and default object

compiler/testData/compileKotlinAgainstKotlin/ClassObjectInEnum.A.kt

@@ -3,7 +3,7 @@ package library
 public enum class EnumClass {
     ENTRY
 
-    public default object {
+    public companion object {
         public fun entry(): EnumClass = ENTRY
     }
 }

compiler/testData/compileKotlinAgainstKotlin/ClassObjectMember.A.kt

@@ -1,5 +1,5 @@
 class A {
-    default object {
+    companion object {
         fun foo() = 42
         val bar = "OK"
     }