Create From Usage: Generate Unit-typed declaration if result is unused

#KT-5903 Fixed

idea/testData/quickfix/createFromUsage/createVariable/localVariable/afterUnitTypedInFun.kt

@@ -0,0 +1,9 @@
+// "Create local variable 'foo'" "true"
+// ACTION: Create parameter 'foo'
+// ERROR: Variable 'foo' must be initialized
+
+fun test() {
+    val foo: Unit
+
+    val u: Unit = foo
+}

idea/testData/quickfix/createFromUsage/createVariable/localVariable/beforeUnitTypedInFun.kt

@@ -0,0 +1,7 @@
+// "Create local variable 'foo'" "true"
+// ACTION: Create parameter 'foo'
+// ERROR: Variable 'foo' must be initialized
+
+fun test() {
+    val u: Unit = <caret>foo
+}