Add aria-selected to ActionList-item for Autocomplete (#2176)

* add aria-selected for autocomplete

* Create tricky-mangos-nail.md

* Stylelint auto-fixes

* stylelint

Co-authored-by: Actions Auto Build <actions@github.com>

Author: langermank

.changeset/tricky-mangos-nail.md

@@ -0,0 +1,5 @@
+---
+"@primer/css": patch
+---
+
+Add `aria-selected` to ActionList-item for Autocomplete

src/actionlist/action-list-item.scss

@@ -115,7 +115,8 @@
 
   // active state [aria-current]
 
-  &.ActionList-item--navActive {
+  &.ActionList-item--navActive,
+  &[aria-selected='true'] {
     &:not(.ActionList-item--subItem) {
       .ActionList-item-label {
         font-weight: $font-weight-bold;