Handle metadata annotations in parameter lists with trailing commas.

test/whitespace/metadata.unit

Index: test/whitespace/metadata.unit
diff --git a/test/whitespace/metadata.unit b/test/whitespace/metadata.unit
index 0c7307655341b4733e6a22291c0e98c302d16ef0..08a39666b719ac6988edf3bd89818bd7dc3f4430 100644
--- a/test/whitespace/metadata.unit
+++ b/test/whitespace/metadata.unit
@@ -209,8 +209,26 @@ named({@foo bar}) {}
 positional([@foo bar]) {}
 named({@foo bar}) {}
 >>> split between metadata and parameter indents
-function(@VeryLongMetadataAnnotation longParameter) {}
+function(@Annotation @VeryLongMetadataAnnotation longParameter) {}
 <<<
 function(
+    @Annotation
     @VeryLongMetadataAnnotation
-        longParameter) {}
+        longParameter) {}
+>>> unsplit with trailing commas
+function(@Annotation longParameter,@Annotation @Other longParameter2,) {}
+<<<
+function(
+  @Annotation longParameter,
+  @Annotation @Other longParameter2,
+) {}
+>>> split with trailing commas
+function(@Annotation longParameter,@Annotation @Other @Third longParameter2,) {}
+<<<
+function(
+  @Annotation longParameter,
+  @Annotation
+  @Other
+  @Third
+      longParameter2,
+) {}