You'll need to create a template override of the following file:
components/com_hotspots/views/hotspots/default.php
here on line 190 you have this code:
<span data-id="<?php echo $cat['id']; ?>" id="cat<?php echo $cat['id']; ?>"
class="hotspots-category-item hasTip "
title="<?php echo $cat['text'] ?>::<?php echo ($cat['cat_description']) ? $cat['cat_description'] : ' '; ?>">
<img border="0" alt="Tooltip" src="<?php echo $path; ?>"/>
</span>
change it to
<span data-id="<?php echo $cat['id']; ?>" id="cat<?php echo $cat['id']; ?>"
class="hotspots-category-item hasTip "
title="<?php echo $cat['text'] ?>::">
<img border="0" alt="Tooltip" src="<?php echo $path; ?>"/>
</span>
That should do the trick

Regards,
Daniel