Add "Make variable immutable" quickfix for const #KT-24263 Fixed

idea/testData/quickfix/typeOfAnnotationMember/string.kt

@@ -1,5 +1,6 @@
 // "Replace array of boxed with array of primitive" "false"
 // ACTION: Put parameters on one line
+// ACTION: Convert to vararg parameter (may break code)
 annotation class SuperAnnotation(
         val str: <caret>Array<String>
 )

idea/testData/quickfix/variables/changeMutability/canBeVal/const.kt

@@ -0,0 +1,4 @@
+// "Make variable immutable" "true"
+object Test {
+    <caret>const var foo = "123"
+}

idea/testData/quickfix/variables/changeMutability/canBeVal/const.kt.after

@@ -0,0 +1,4 @@
+// "Make variable immutable" "true"
+object Test {
+    <caret>const val foo = "123"
+}