moved here from the task https://phabricator.wikimedia.org/T293229
"But for reference... I really like this implementation shown here -> https://codepen.io/CSWApps/pen/RQbvvp (this would be cool). But if we do any counter at all, at a minimum we should have one under the text area in small type like "X characters left" where default would be "480 character left" (similar to this: https://codepen.io/bawdyBunny/pen/qBEzPyW) and it updates as they type. Not a huge deal though."