$string['quizclose'] used where $string['quizcloses'] would be more appropriate

I think perhaps the wrong $string is being used for the following:
On this page:
/mod/quiz/view.php?id=5796
You have ...
$string['quizclose'] = 'Close the quiz';
... when I think it would be more appropriate to have ...
$string['quizcloses'] = 'Quiz closes';

In the same place, the strings related to opening the quiz, should probably be changed.

These are the 4 strings copied from the English language pack.
$string['quizclose'] = 'Close the quiz';
$string['quizcloses'] = 'Quiz closes';
$string['quizopen'] = 'Open the quiz';
$string['quizopens'] = 'Quiz opens';