docs(readme): Make sure <datetimepicker> elements are closed with </datetimepicker>

Preventing any copy-paste errors that might result from self-closing <datetimepicker> elements in

the docs.

Author: dalelotts

README.md

@@ -348,7 +348,7 @@ the drop-down is toggled closed after the user selectes a date/time.
     </div>
   </a>
   <ul class="dropdown-menu" role="menu" aria-labelledby="dLabel">
-    <datetimepicker data-ng-model="dateRangeStart" data-datetimepicker-config="{ dropdownSelector: '#dropdown1'}" data-before-render="beforeRenderStartDate($view, $dates, $leftDate, $upDate, $rightDate)"/>
+    <datetimepicker data-ng-model="dateRangeStart" data-datetimepicker-config="{ dropdownSelector: '#dropdown1'}" data-before-render="beforeRenderStartDate($view, $dates, $leftDate, $upDate, $rightDate)"></datetimepicker>
   </ul>
 </div>
 
@@ -360,7 +360,7 @@ the drop-down is toggled closed after the user selectes a date/time.
     </div>
   </a>
   <ul class="dropdown-menu" role="menu" aria-labelledby="dLabel">
-    <datetimepicker data-ng-model="dateRangeEnd" data-datetimepicker-config="{ dropdownSelector: '#dropdown2'}" data-before-render="beforeRenderEndDate($view, $dates, $leftDate, $upDate, $rightDate)"/>
+    <datetimepicker data-ng-model="dateRangeEnd" data-datetimepicker-config="{ dropdownSelector: '#dropdown2'}" data-before-render="beforeRenderEndDate($view, $dates, $leftDate, $upDate, $rightDate)"></datetimepicker>
   </ul>
 </div>
 ```