Renamed {{scroll-to}}'s shouldScroll argument to when

no issue

- `when` makes the modifier a little easier to read for it's typical use-case, eg:
  - `{{scroll-to when=(eq entry.slug this.entry)}}`
  - `{{scroll-to when=(eq this.focusArea "analytics")}}`

ghost/admin/app/modifiers/scroll-to.js

@@ -1,9 +1,9 @@
 import getScrollParent from 'ghost-admin/utils/get-scroll-parent';
 import {modifier} from 'ember-modifier';
 
-export default modifier((element, positional, {shouldScroll = true}) => {
-    if (shouldScroll) {
-        // setTimeout needed to ensure layout has finished and we have accurate
+export default modifier((element, positional, {when = true}) => {
+    if (when) {
+        // setTimeout needed to ensure layout has finished and we have accurate positioning
         setTimeout(() => {
             const scrollParent = getScrollParent(element);
             const y = element.offsetTop;

ghost/admin/app/templates/whatsnew.hbs

@@ -7,7 +7,7 @@
         <div class="gh-about-container">
             <section class="gh-whats-new gh-about-box" {{did-insert (perform this.whatsNew.updateLastSeen)}}>
                 {{#each this.whatsNew.entries as |entry|}}
-                    <div class="gh-wn-entry" {{scroll-to shouldScroll=(eq entry.slug this.entry)}}>
+                    <div class="gh-wn-entry" {{scroll-to when=(eq entry.slug this.entry)}}>
                         <a href="{{entry.url}}">
                             <h4>{{moment-format entry.published_at "DD MMMM YYYY"}}</h4>
                             <h1>{{entry.title}}</h1>