obsolete: fix old typo
Clean an old typo in successorssets.
Differential Revision: https://phab.mercurial-scm.org/D531
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<link rel="icon" href="{staticurl|urlescape}hgicon.png" type="image/png">
<meta name="robots" content="index, nofollow" />
<link rel="stylesheet" href="{staticurl|urlescape}style.css" type="text/css" />
<script type="text/javascript" src="{staticurl|urlescape}mercurial.js"></script>