feat: add highlight selection to S2 TreeView (adobe#9769)

* Merge branch 'main' into tree-section

* feat: add highlight selection to TreeView

* clean up

* fixes

* update comment

* add highlight selection to docs

* update hcm

* update chromatic

* fix forced colors error

* add highlight selection to docs

* export isPrevSelected from ListView

* add link to jsdoc

* export additional functions

* update focus ring

* add hcm back for focus ring

* prevent focus ring from getting cut off when inside selected group

Author: yihuiliao

packages/@react-spectrum/s2/chromatic/TreeView.stories.tsx

@@ -143,14 +143,23 @@ export const TreeStatic: StoryObj<typeof TreeExample> = {
   render: (args) => <TreeExample {...args} />
 };
 
-export const TreeSelection: StoryObj<typeof TreeExample> = {
+export const TreeCheckboxSelection: StoryObj<typeof TreeExample> = {
   ...TreeStatic,
   args: {
     selectionMode: 'multiple',
     defaultSelectedKeys: ['projects-2', 'projects-3']
   }
 };
 
+export const TreeHighlightSelection: StoryObj<typeof TreeExample> = {
+  ...TreeStatic,
+  args: {
+    selectionMode: 'multiple',
+    selectionStyle: 'highlight',
+    defaultSelectedKeys: ['projects-2', 'projects-3']
+  }
+};
+
 export const TreeDisableSelection: StoryObj<typeof TreeExample> = {
   ...TreeStatic,
   args: {

packages/@react-spectrum/s2/src/ListView.tsx

@@ -716,15 +716,15 @@ function isNextSelected(id: Key | undefined, state: ListState<unknown>) {
   let keyAfter = state.collection.getKeyAfter(id);
   return keyAfter != null && state.selectionManager.isSelected(keyAfter);
 }
-function isPrevSelected(id: Key | undefined, state: ListState<unknown>) {
+export function isPrevSelected(id: Key | undefined, state: ListState<unknown>) {
   if (id == null || !state) {
     return false;
   }
   let keyBefore = state.collection.getKeyBefore(id);
   return keyBefore != null && state.selectionManager.isSelected(keyBefore);
 }
 
-function isFirstItem(id: Key | undefined, state: ListState<unknown>) {
+export function isFirstItem(id: Key | undefined, state: ListState<unknown>) {
   if (id == null || !state) {
     return false;
   }