XWIKI-22276: Panel reference lists for columns' hint is not precise enough

* Updated the default (english) hint to make it easier to use this feature

(cherry picked from commit ea740a9c)

xwiki-platform-core/xwiki-platform-oldcore/src/main/resources/ApplicationResources.properties

@@ -3359,7 +3359,7 @@ XWiki.XWikiPreferences_edit_registered=Registered
 XWiki.XWikiPreferences_comment_anonymous=Anonymous
 XWiki.XWikiPreferences_comment_registered=Registered
 XWiki.XWikiPreferences_leftPanels=Panels displayed on the left
-XWiki.XWikiPreferences_leftPanels.hint=A comma separated list of panels to display on the left column. E.g.: Panels.Applications, Panels.Navigation
+XWiki.XWikiPreferences_leftPanels.hint=A comma separated list of panels to display on the left column. The panel page references should be used. Such references can be found in the information tab on the bottom of the page itself. E.g.: Panels.Applications, Panels.Navigation
 XWiki.XWikiPreferences_rightPanels=Panels displayed on the right
 XWiki.XWikiPreferences_rightPanels.hint=A comma separated list of panels to display on the right column.
 XWiki.XWikiPreferences_showLeftPanels=Display the left panel column