I don’t think this can be done straight from the dashboard, but with a little CSS you can have your lists show ABC and abc!
You just need to make a child theme and edit your style.css and add a class or edit the OL/UL classes. If you do want all of your lists to say ABC or abc then you can just edit the list-style to: upper-latin or lower-latin
If you don’t then just make a class (example below) like this:
.alphabet ul {
list-style: lower-latin;
}
Then call the class in your post/page editor (change to the HTML view) and add a class value to your UL (or OL) so like this:
<ul class="alphabet">
This is all I can think of to help you ?? let me know if I can explain anything a bit clearer.
Megan