docs: adds info on useSelection and useStepNav hooks (#10683)

### What?
This PR adds information and examples on the `useSelection` and
`useStepNav` hooks.

### Why?
To provide more information on the React hooks available to end-users.

### How?
Changes to `admin/hooks.mdx`

docs/admin/hooks.mdx

@@ -764,6 +764,45 @@ The `useListQuery` hook returns an object with the following properties:
 | **`handleWhereChange`** | A method to handle where changes in the List View.                                       |
 | **`query`**       | The current query that is being used to fetch the data in the List View.                             |
 
+## useSelection
+
+The `useSelection` hook provides information on the selected rows in the List view as well as helper methods to simplify selection. The `useSelection` hook returns an object with the following properties:
+
+| Property             | Description                                                                                                                                                               |
+| -------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
+| **`count`**          | The number of currently selected rows.                                                                                                                                    |
+| **`getQueryParams`** | A function that generates a query string based on the current selection state and optional additional filtering parameters.                                               |
+| **`selectAll`**      | An enum value representing the selection range: `'allAvailable'`, `'allInPage'`, `'none'`, and `'some'`. The enum, `SelectAllStatus`, is exported for easier comparisons. |
+| **`selected`**       | A map of document id keys and boolean values representing their selection status.                                                                                         |
+| **`setSelection`**   | A function that toggles the selection status of a document row.                                                                                                           |
+| **`toggleAll`**      | A function that toggles selection for all documents on the current page or selects all available documents when passed `true`.                                            |
+| **`totalDocs`**      | The number of total documents in the collection.                                                                                                                          |
+
+**Example:**
+
+```tsx
+'use client'
+import { useSelection } from '@payloadcms/ui'
+
+const MyComponent: React.FC = () => {
+  // highlight-start
+  const { count, toggleAll, totalDocs } = useSelection()
+  // highlight-end
+
+  return (
+    <>
+      <span>Selected {count} out of {totalDocs} docs!</span>
+      <button
+        type="button"
+        onClick={() => toggleAll(true)}
+      >
+        Toggle All Selections
+      </button>
+    </>
+  )
+}
+```
+
 ## useLocale
 
 In any Custom Component you can get the selected locale object with the `useLocale` hook. `useLocale` gives you the full locale object, consisting of a `label`, `rtl`(right-to-left) property, and then `code`. Here is a simple example:
@@ -948,3 +987,32 @@ const ListenForUpdates: React.FC = () => {
   Right now the `useDocumentEvents` hook only tracks recently updated documents, but in the future
   it will track more document-related events as needed, such as document creation, deletion, etc.
 </Banner>
+
+## useStepNav
+
+The `useStepNav` hook provides a way to change the step-nav breadcrumb links in the app header.
+
+| Property         | Description                                                                       |
+| ---------------- | --------------------------------------------------------------------------------- |
+| **`setStepNav`** | A state setter function which sets the `stepNav` array.                           |
+| **`stepNav`**    | A `StepNavItem` array where each `StepNavItem` has a label and optionally a url.  |
+
+**Example:**
+
+```tsx
+'use client'
+import { type StepNavItem, useStepNav } from '@payloadcms/ui'
+import { useEffect } from 'react'
+
+export const MySetStepNavComponent: React.FC<{
+  nav: StepNavItem[]
+}> = ({ nav }) => {
+  const { setStepNav } = useStepNav()
+
+  useEffect(() => {
+    setStepNav(nav)
+  }, [setStepNav, nav])
+
+  return null
+}
+```