remove trailing white spaces

tests/inputdialog.lua

@@ -15,7 +15,7 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
+--
 -- Copyright (C) 2015-2020, TBOOX Open Source Group.
 --
 -- @author      ruki
@@ -38,7 +38,7 @@ local demo = application()
 -- init demo
 function demo:init()
 
-    -- init name 
+    -- init name
     application.init(self, "demo")
 
     -- init background