fix #258, properly update Checklist widgets at updating the note

Author: tibbi

app/src/main/kotlin/com/simplemobiletools/notes/pro/fragments/ChecklistFragment.kt

@@ -123,6 +123,7 @@ class ChecklistFragment : NoteFragment(), ChecklistItemsListener {
 
                 note!!.value = Gson().toJson(items)
                 context?.notesDB?.insertOrUpdate(note!!)
+                context?.updateWidgets()
             }
         }.start()
     }