Minor formatting fixes (no logical changes) (#13855)

Reformats a SafeArea introduced in #13853.

examples/flutter_gallery/lib/demo/animation/widgets.dart

@@ -142,7 +142,11 @@ class SectionDetailView extends StatelessWidget {
       item = new Container(
         height: 240.0,
         padding: const EdgeInsets.all(16.0),
-        child: new SafeArea(top: false, bottom:false, child: image),
+        child: new SafeArea(
+          top: false,
+          bottom: false,
+          child: image,
+        ),
       );
     } else {
       item = new ListTile(