Fix broken link

Author: mborland

doc/supplemental-ui/partials/header-content.hbs

@@ -1,7 +1,7 @@
 <header class="header">
   <nav class="navbar">
     <div class="navbar-brand">
-      <a class="navbar-item" href="{{{or site.url siteRootPath}}}">{{site.title}}</a>
+      <a class="navbar-item" href="https://github.com/cppalliance/decimal">{{site.title}}</a>
       {{#if env.SITE_SEARCH_PROVIDER}}
       <div class="navbar-item search hide-for-print">
         <div id="search-field" class="field">