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

idea/testData/diagnosticMessage/nestedClassAcessedViaInstanceReference.kt

@@ -3,7 +3,7 @@
 
 class A {
     class Nested()
-    class NestedWithClassObject { default object }
+    class NestedWithClassObject { companion object }
     enum class NestedEnum { A }
     object NestedObj { fun invoke() = 1 }
 }

idea/testData/diagnosticMessage/nestedClassAcessedViaInstanceReference2.txt

@@ -1,2 +1,2 @@
 <!-- nestedClassAcessedViaInstanceReference2 -->
-Nested default object 'Default' accessed via instance reference
+Nested companion object 'Companion' accessed via instance reference

idea/testData/diagnosticMessage/nestedClassShouldBeQualified.kt

@@ -15,21 +15,21 @@ fun A.B.test() {
 }
 
 class C {
-    default object {
+    companion object {
         class D {
             class Nested
         }
     }
 }
 
-fun C.Default.D.text() {
+fun C.Companion.D.text() {
     Nested()
     ::Nested
 }
 
 class E {
     class F {
-        default object
+        companion object
     }
 }
 

idea/testData/diagnosticMessage/nestedClassShouldBeQualified3.txt

@@ -1,2 +1,2 @@
 <!-- nestedClassShouldBeQualified3 -->
-Nested class 'Nested' should be qualified as 'C.Default.D.Nested'
+Nested class 'Nested' should be qualified as 'C.Companion.D.Nested'

idea/testData/diagnosticMessage/nestedClassShouldBeQualified4.txt

@@ -1,2 +1,2 @@
 <!-- nestedClassShouldBeQualified4 -->
-Nested class 'Nested' should be qualified as 'C.Default.D::Nested'
+Nested class 'Nested' should be qualified as 'C.Companion.D::Nested'

idea/testData/diagnosticMessage/nestedClassShouldBeQualified5.txt

@@ -1,2 +1,2 @@
 <!-- nestedClassShouldBeQualified5 -->
-Nested default object 'Default' should be qualified as 'E.F.Default'
+Nested companion object 'Companion' should be qualified as 'E.F.Companion'