accessibility: list role for lists, listbox for suggestWidget

#92483

src/vs/base/browser/ui/list/list.ts

@@ -65,7 +65,7 @@ export interface IIdentityProvider<T> {
 
 export enum ListAriaRootRole {
 	/** default list structure role */
-	LIST = 'listbox',
+	LIST = 'list',
 
 	/** default tree structure role */
 	TREE = 'tree',

src/vs/editor/contrib/suggest/suggestWidget.ts

@@ -604,6 +604,12 @@ export class SuggestWidget implements IContentWidget, IListVirtualDelegate<Compl
 			useShadows: false,
 			openController: { shouldOpen: () => false },
 			mouseSupport: false,
+			ariaRole: 'listbox',
+			ariaProvider: {
+				getRole: () => 'option',
+				getSetSize: (_: CompletionItem, _index: number, listLength: number) => listLength,
+				getPosInSet: (_: CompletionItem, index: number) => index,
+			},
 			accessibilityProvider: {
 				getAriaLabel: (item: CompletionItem) => {
 					const textLabel = typeof item.completion.label === 'string' ? item.completion.label : item.completion.label.name;