Fix a typo in assignment properties

assignment/assignment-bundles/resources/assignment.properties

@@ -921,7 +921,7 @@ sendFeedback.label = Select user(s) to send feedback
 sendFeedback.instruction = Select user(s) and write feedback in text area below
 sendFeedback.options = Feedback options
 sendFeedback.overwrite = Overwrite current feedback (NOTE: It does not override by default).
-sendFeedback.returnToStudents = Return feedback to selected students now (NOTE: This opction only returns the feedback, if you wish to publish grades, you will need to click on 'Release grades').
+sendFeedback.returnToStudents = Return feedback to selected students now (NOTE: This option only returns the feedback, if you wish to publish grades, you will need to click on 'Release grades').
 sendFeedback.nouser = Please choose at least one user for sending feedback.
 sendFeedback.nocomment = Please introduce a feedback comment. 
 sendFeedback.savedow = Feedback has been overwritten and saved successfully.