Enhancement for "join declaration and assignment": now can handle also local variables, relevant inspection added #KT-12095 Fixed

idea/testData/intentions/joinDeclarationAndAssignment/singleConstructor.kt

@@ -0,0 +1,7 @@
+class A {
+    constructor() {
+        a = 1
+    }
+
+    val a<caret>: Int
+}