Create from usage: make new member function/property private by default

#KT-6689 Fixed

idea/testData/quickfix/createFromUsage/createFunction/get/afterCreateGetFromUsage3.kt

@@ -4,7 +4,7 @@ class Foo<T> {
         val z: Iterable<S> = y[""]
     }
 
-    fun get(s: String): T {
+    private fun get(s: String): T {
         throw UnsupportedOperationException("not implemented") //To change body of created functions use File | Settings | File Templates.
     }
 }