Change Signature: Support implicit calls of 'invoke' and 'get'

Also drop 'operator' keyword when necessary

 #KT-22718 Fixed

idea/testData/refactoring/changeSignature/GetConventionRemoveParameterAfter.kt

@@ -0,0 +1,9 @@
+class A {
+    operator fun get(i: Int) {}
+}
+
+fun usage(a: A) {
+    a[42]
+    A()[42]
+    a.get(42)
+}