Create From Usage ("set" operation): Support expressions of the form a[i]++

idea/testData/quickfix/createFromUsage/createFunction/set/afterSetterForIncrement.kt

@@ -0,0 +1,13 @@
+// "Create function 'set' from usage" "true"
+class A {
+    fun get(s: String): Int = 1
+
+    fun set(s: String, value: Int) {
+        throw UnsupportedOperationException("not implemented") //To change body of created functions use File | Settings | File Templates.
+    }
+}
+
+fun foo() {
+    var a = A()
+    a["1"]++
+}

idea/testData/quickfix/createFromUsage/createFunction/set/beforeSetterForIncrement.kt

@@ -0,0 +1,9 @@
+// "Create function 'set' from usage" "true"
+class A {
+    fun get(s: String): Int = 1
+}
+
+fun foo() {
+    var a = A()
+    a<caret>["1"]++
+}