Support for import aliases in code completion

#KT-8848 Fixed

idea/idea-completion/testData/basic/java/importAliases/TopLevelFun.kt

@@ -0,0 +1,7 @@
+import kotlin.collections.listOf as list
+
+fun foo() {
+    lis<caret>
+}
+
+// EXIST: { lookupString: "list", itemText: "list", tailText: "() (kotlin.collections.listOf)" }