Replace 'class object' with 'default object' in renderers and test data

Includes changes to decompiled text
Old syntax is used in builtins and project code for now

idea/testData/decompiler/navigation/decompiled/WithInnerAndObject.kt

@@ -4,7 +4,7 @@
 package testData.libraries
 
 [[public final class WithInnerAndObject() {
-    [[public class object {
+    [[public default object {
         [internal final fun foo(): kotlin.Unit { /* compiled code */ }]
     }]]
 

idea/testData/decompiler/navigation/decompiled/WithTraitClassObject.kt

@@ -4,6 +4,6 @@
 package testData.libraries
 
 [[public final class WithTraitClassObject() {
-    [[public class object : testData.libraries.SimpleTrait {
+    [[public default object : testData.libraries.SimpleTrait {
     }]]
 }]]

idea/testData/decompiler/navigation/library/main.kt

@@ -10,7 +10,7 @@ public class SimpleTraitImpl : SimpleTrait {
 }
 
 public class WithInnerAndObject {
-    class object {
+    default object {
         fun foo() {
         }
     }
@@ -23,7 +23,7 @@ public class WithInnerAndObject {
 }
 
 public class WithTraitClassObject {
-    class object : SimpleTrait
+    default object : SimpleTrait
 }
 
 public abstract class AbstractClass {

idea/testData/decompiler/navigation/usercode/ClassObject.kt

@@ -5,5 +5,5 @@ fun foo() {
 }
 
 // main.kt
-//    class <1>object {
+//    default <1>object {
 //        fun <2>foo() {