XWIKI-22169: Breadcrumb dropdowns for navigation should be keyboard accessible (#3376)

* Added a label to the tree toggle button

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

@@ -4022,6 +4022,8 @@ rating.votes=Votes
 ## Hierarchy
 web.hierarchy.error=Failed to get the full hierarchy.
 web.hierarchy.label=Breadcrumb
+web.hierarchy.toggler.label.children=Toggle the hierarchy tree under {0}.
+web.hierarchy.toggler.label.parents=Toggle the parent tree of {0}.
 
 ## XWiki Select Widget
 web.widgets.select.filter=Filter

xwiki-platform-core/xwiki-platform-web/xwiki-platform-web-templates/src/main/resources/templates/hierarchy_macros.vm

@@ -221,7 +221,14 @@
       'showTranslations': $xwiki.isMultiLingual(),
       'showWikis': $showWikis
     })
+    #if ($rootId)
+      #set ($togglerTextAlternative = "<span class='sr-only'>$escapetool.xml($services.localization.render('web.hierarchy.toggler.label.children', [$pathData.get($openToIndex).label])) </span>")
+    #else
+      ## If the rootId is null, this means that the root is the home. Which means that we're on the first tree, which doesn't show exactly the same thing as the others.
+      #set ($togglerTextAlternative = "<span class='sr-only'>$escapetool.xml($services.localization.render('web.hierarchy.toggler.label.parents', [$pathData.get($openToIndex).label])) </span>")
+    #end
     #set ($treeToggle = "<button class='dropdown-toggle' data-toggle='dropdown'>" +
+      $togglerTextAlternative +
       "$services.icon.renderHTML('caret-down')</button>")
     #set ($treeNavigation = "$treeToggle<div class='dropdown-menu'>#documentTree($treeParams)</div>")
   #end