Update useIsRouting reference page (#1400)

Co-authored-by: kodiakhq[bot] <49736102+kodiakhq[bot]@users.noreply.github.com>

Author: amirhhashemi

src/routes/solid-router/reference/primitives/use-is-routing.mdx

@@ -9,21 +9,56 @@ tags:
   - pending
   - state
   - ui
-version: '1.0'
+version: "1.0"
 description: >-
   Track route transitions with useIsRouting - display loading states, pending
   UI, and transition feedback during navigation in SolidJS.
 ---
 
-Retrieves a signal that indicates whether the route is currently in a transition.
-This is useful for showing a stale or pending state when the route resolution is suspended state during concurrent rendering.
+The `useIsRouting` function is a utility for detecting when the router is processing a route transition.
 
-```js
-const isRouting = useIsRouting();
+## Import
 
-return (
-	<div classList={{ "grey-out": isRouting() }}>
-		<MyAwesomeContent />
-	</div>
-);
+```ts
+import { useIsRouting } from "@solidjs/router";
 ```
+
+## Type
+
+```ts
+const useIsRouting: () => () => boolean;
+```
+
+## Parameters
+
+None.
+
+## Return value
+
+**Type:** `() => boolean`
+
+An accessor function that returns `true` during route transitions and `false` otherwise.
+
+## Examples
+
+### Route transition indicator
+
+```tsx
+import { useIsRouting } from "@solidjs/router";
+
+function App() {
+	const isRouting = useIsRouting();
+
+	return (
+		<>
+			{isRouting() && <div class="loading-bar" />}
+			<MyContent />
+		</>
+	);
+}
+```
+
+## Related
+
+- [`<Router>`](/solid-router/reference/components/router)
+- [`useNavigate`](/solid-router/reference/primitives/use-navigate)