Resource Bundles: Enable property key completion in string literals

#KT-6946 Fixed

idea/idea-completion/testData/basic/multifile/PropertyKeysEmptyString/PropertyKeysEmptyString.dependency.kt

@@ -0,0 +1,5 @@
+package org.jetbrains.annotations
+
+@Retention(AnnotationRetention.BINARY)
+@Target(AnnotationTarget.VALUE_PARAMETER, AnnotationTarget.LOCAL_VARIABLE, AnnotationTarget.FIELD)
+public annotation class PropertyKey(public val resourceBundle: String)

idea/idea-completion/testData/basic/multifile/PropertyKeysEmptyString/PropertyKeysEmptyString.kt

@@ -0,0 +1,13 @@
+import org.jetbrains.annotations.PropertyKey
+
+fun message(@PropertyKey(resourceBundle = "PropertyKeysEmptyString") key: String) = key
+
+fun test() {
+    message("<caret>")
+}
+
+// EXIST: { lookupString: "foo.bar", itemText: "foo.bar", tailText: "1", typeText: "PropertyKeysEmptyString" }
+// EXIST: { lookupString: "bar.baz", itemText: "bar.baz", tailText: "2", typeText: "PropertyKeysEmptyString" }
+// EXIST: { lookupString: "foo.bar.baz", itemText: "foo.bar.baz", tailText: "3", typeText: "PropertyKeysEmptyString" }
+// EXIST: { lookupString: "foo.test", itemText: "foo.test", tailText: "4", typeText: "PropertyKeysEmptyString" }
+// NOTHING_ELSE

idea/idea-completion/testData/basic/multifile/PropertyKeysEmptyString/PropertyKeysEmptyString.properties

@@ -0,0 +1,4 @@
+foo.bar = 1
+bar.baz = 2
+foo.bar.baz = 3
+foo.test = 4