Expect/actual companion object: set gutter on leaf element

May fix KT-21113

idea/testData/multiModuleLineMarker/fromExpectCompanion/common/common.kt

@@ -0,0 +1,5 @@
+expect class <lineMarker>WithCompanion</lineMarker> {
+    companion <lineMarker>object</lineMarker> {
+
+    }
+}