Only named parameters in completion when nothing else can be

compiler/frontend/src/org/jetbrains/jet/lang/psi/JetCallElement.java

@@ -16,6 +16,7 @@
 
 package org.jetbrains.jet.lang.psi;
 
+import kotlin.jvm.KotlinSignature;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -28,6 +29,7 @@ public interface JetCallElement extends JetElement {
     @Nullable
     JetValueArgumentList getValueArgumentList();
 
+    @KotlinSignature("fun getValueArguments(): List<out ValueArgument>")
     @NotNull
     List<? extends ValueArgument> getValueArguments();