Always split collections and argument lists with trailing commas.

test/whitespace/expressions.stmt

Index: test/whitespace/expressions.stmt
diff --git a/test/whitespace/expressions.stmt b/test/whitespace/expressions.stmt
index cf241ebd9950675bce40babf4b6b8bee221b5566..310e7bdcb0611935f281498ff4b62afa56035d45 100644
--- a/test/whitespace/expressions.stmt
+++ b/test/whitespace/expressions.stmt
@@ -118,12 +118,20 @@ variableName ??= argument;
 >>> trailing comma in single argument list
 function(argument   ,   );
 <<<
-function(argument,);
+function(
+  argument,
+);
 >>> trailing comma in argument list
 function(argument,argument  ,  );
 <<<
-function(argument, argument,);
+function(
+  argument,
+  argument,
+);
 >>> trailing comma in named argument list
 function(named: arg,another:arg,  );
 <<<
-function(named: arg, another: arg,);
+function(
+  named: arg,
+  another: arg,
+);