Fix dangling comments for arrays (#665)

It was missing a softline. I copy and pasted the dangling handling for objects.

Fixes #624

src/printer.js

@@ -712,7 +712,14 @@ function genericPrintNoParens(path, options, print) {
     case "ArrayPattern":
       if (n.elements.length === 0) {
         parts.push(
-          concat(["[", comments.printDanglingComments(path, options), "]"])
+          group(
+            concat([
+              "[",
+              comments.printDanglingComments(path, options),
+              softline,
+              "]"
+            ])
+          )
         );
       } else {
         const lastElem = util.getLast(n.elements);

tests/comments/__snapshots__/jsfmt.spec.js.snap

@@ -74,6 +74,32 @@ declare class Foo extends Qux<string> {/* dangling */}
 "
 `;
 
+exports[`test dangling_array.js 1`] = `
+"expect(() => {}).toTriggerReadyStateChanges([
+  // Nothing.
+]);
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+expect(() => {}).toTriggerReadyStateChanges(
+  [
+    // Nothing.
+  ]
+);
+"
+`;
+
+exports[`test dangling_array.js 2`] = `
+"expect(() => {}).toTriggerReadyStateChanges([
+  // Nothing.
+]);
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+expect(() => {}).toTriggerReadyStateChanges(
+  [
+    // Nothing.
+  ]
+);
+"
+`;
+
 exports[`test first-line.js 1`] = `
 "a // comment
 b

tests/comments/dangling_array.js

@@ -0,0 +1,3 @@
+expect(() => {}).toTriggerReadyStateChanges([
+  // Nothing.
+]);