Fix broken help link

closes TryGhost/Ghost#9536

app/templates/components/gh-nav-menu.hbs

@@ -15,7 +15,7 @@
             <li role="presentation">{{#link-to "team.user" session.user.slug classNames="dropdown-item user-menu-profile js-nav-item" role="menuitem" tabindex="-1"}}{{svg-jar "user-circle"}} Your Profile{{/link-to}}</li>
             <li role="presentation"><a class="dropdown-item help-menu-support" role="menuitem" tabindex="-1" href="https://help.ghost.org/" target="_blank">{{svg-jar "ambulance"}} Support Center</a></li>
             <li role="presentation"><a class="dropdown-item help-menu-tweet" role="menuitem" tabindex="-1" href="https://twitter.com/intent/tweet?text=%40TryGhost+Hi%21+Can+you+help+me+with+&related=TryGhost" target="_blank" onclick="window.open(this.href, 'twitter-share', 'width=550,height=235');return false;">{{svg-jar "twitter"}} Tweet @TryGhost!</a></li>
-            <li role="presentation"><a class="dropdown-item help-menu-how-to" role="menuitem" tabindex="-1" href="https://ghosthelp.zendesk.com/hc/en-us/categories/203268947-Ghost-Pro-" target="_blank">{{svg-jar "book-open"}} How to Use Ghost</a></li>
+            <li role="presentation"><a class="dropdown-item help-menu-how-to" role="menuitem" tabindex="-1" href="https://help.ghost.org/article/7-how-to-use-ghost" target="_blank">{{svg-jar "book-open"}} How to Use Ghost</a></li>
             <li class="divider"></li>
 
             {{#if showDropdownExtension}}