Fix "Add function to supertype" braces #KT-23215 Fixed

idea/src/org/jetbrains/kotlin/idea/quickfix/AddFunctionToSupertypeFix.kt

@@ -143,7 +143,7 @@ class AddFunctionToSupertypeFix private constructor(
                         functionDescriptor.returnType?.let { IdeDescriptorRenderers.SOURCE_CODE.renderType(it) } ?: "Unit",
                         classDescriptor.importableFqName
                     )
-                    "{ $bodyText }"
+                    "{\n$bodyText\n}"
                 } else {
                     "{}"
                 }

idea/testData/quickfix/override/nothingToOverride/addFunctionNonUnitReturnType.kt.after

@@ -2,7 +2,8 @@
 // WITH_RUNTIME
 open class A {
     open fun f(): Int {
-        TODO("not implemented") //To change body of created functions use File | Settings | File Templates. }
+        TODO("not implemented") //To change body of created functions use File | Settings | File Templates.
+    }
 }
 class B : A() {
     <caret>override fun f(): Int = 5