docs: support multiple sidebars in a project (#11768)

* changed to new sidebar across projects except resources

* finalize multi sidebar support

* clean up

* remove redundant property

* small changes

* fixes

* generate

* fix error

* fix initial open

www/apps/book/utils/sidebar-attach-common-options.mjs

@@ -1,31 +0,0 @@
-/** @type {Partial<import("@/types").SidebarItem[]>} */
-const commonOptions = {
-  loaded: true,
-  isPathHref: true,
-}
-
-/**
- *
- * @param {import("@/types").SidebarItem[]} sidebar
- * @param {boolean} nested
- * @returns {import("@/types").SidebarItem[]}
- */
-export function sidebarAttachHrefCommonOptions(sidebar, nested = false) {
-  return sidebar.map((item) => {
-    if (item.type === "separator") {
-      return item
-    }
-
-    const updatedItem = {
-      ...commonOptions,
-      ...item,
-      children: sidebarAttachHrefCommonOptions(item.children || [], true),
-    }
-
-    if (updatedItem.type !== "category" && !nested) {
-      updatedItem.childrenSameLevel = true
-    }
-
-    return updatedItem
-  })
-}