docs: improve server routes guide (#4401)

docs/content/2.guide/2.features/9.server-routes.md

@@ -9,7 +9,7 @@ The handler can directly return JSON data, a `Promise` or use `event.res.end()`
 ::ReadMore{link="https://nitro.unjs.io/guide/routing.html" title="Nitro Route Handling Docs"}
 ::
 
-## Usage Example
+## Example
 
 Create a new file in `server/api/hello.ts`:
 
@@ -60,7 +60,18 @@ export default defineEventHandler((event) => {
 })
 ```
 
-## Matching Route Parameters
+## Server Utilities
+
+Server routes are powered by [unjs/h3](https://github.com/unjs/h3) which comes with a handy set of helpers.
+
+::ReadMore{link="https://www.jsdocs.io/package/h3#package-index-functions" title="Available H3 Request Helpers"}
+::
+
+You can add more helpers by yourself inside the `~/server/utils` directory.
+
+## Usage Examples
+
+### Matching Route Parameters
 
 Server routes can use dynamic parameters within brackets in the file name like `/api/hello/[name].ts` and accessed via `event.context.params`.
 
@@ -72,7 +83,7 @@ export default defineEventHandler(event => `Hello, ${event.context.params.name}!
 
 You can now universally call this API using `await $fetch('/api/hello/nuxt')` and get `Hello, nuxt!`.
 
-## Matching HTTP Method
+### Matching HTTP Method
 
 Handle file names can be suffixed with `.get`, `.post`, `.put`, `.delete`, ... to match request's [HTTP Method](https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods).
 
@@ -90,7 +101,7 @@ Given the Example above, fetching `/test` with:
 - **POST** method: Returns `Test post handler`
 - Any other method: Returns 404 error
 
-## Catch-all route
+### Catch-all route
 
 Catch-all routes are helpful for fallback route handling. For Example, creating a file in the `~/server/api/foo/[...].ts` will register a catch-all route for all requests that do not match any route handler, such as `/api/foo/bar/baz`.
 
@@ -104,7 +115,7 @@ export default defineEventHandler(() => `Default foo handler`)
 export default defineEventHandler(() => `Default api handler`)
 ```
 
-## Handling Requests with Body
+### Handling Requests with Body
 
 ```ts [/server/api/submit.post.ts]
 export default defineEventHandler(async (event) => {
@@ -119,7 +130,28 @@ You can now universally call this API using `$fetch('/api/submit', { method: 'po
 We are using `submit.post.ts` in the filename only to match requests with `POST` method that can accept the request body. When using `useBody` within a GET request, `useBody` will throw a `405 Method Not Allowed` HTTP error.
 ::
 
-## Access Request Cookies
+### Handling Requests with query parameters
+
+Sample query `/api/query?param1=a&param2=b`
+
+```ts [/server/api/query.get.ts]
+export default defineEventHandler((event) => {
+  const query = useQuery(event)
+  return { a: query.param1, b: query.param2 }
+})
+```
+
+### Get access to the runtimeConfig
+
+```ts [/server/api/foo.ts]
+
+export default defineEventHandler((event) => {
+  const config = useRuntimeConfig()
+  return { key: config.KEY }
+})
+```
+
+### Access Request Cookies
 
 ```ts
 export default defineEventHandler((event) => {
@@ -128,7 +160,9 @@ export default defineEventHandler((event) => {
 })
 ```
 
-## Using a nested router
+## Advanced Usage Examples
+
+### Using a nested router
 
 ```ts [/server/api/hello.ts]
 import { createRouter } from 'h3'
@@ -140,7 +174,20 @@ router.get('/', () => 'Hello World')
 export default router
 ```
 
-## Return a legacy handler or middleware
+### Sending streams (experimental)
+
+**Note:** This is an experimental feature and available only within Node.js environments.
+
+```ts [/server/api/foo.get.ts]
+import fs from 'node:fs'
+import { sendStream } from 'h3'
+
+export default defineEventHandler((event) => {
+  return sendStream(event, fs.createReadStream('/path/to/file'))
+})
+```
+
+### Return a legacy handler or middleware
 
 ```ts [/server/api/legacy.ts]
 export default (req, res) => {
@@ -162,12 +209,3 @@ export default (req, res, next) => {
 ::alert{type=warning}
 Never combine `next()` callback with a legacy middleware that is `async` or returns a `Promise`!
 ::
-
-## Server Utils
-
-Server routes are powered by [unjs/h3](https://github.com/unjs/h3) which comes with a handy set of helpers.
-
-::ReadMore{link="https://www.jsdocs.io/package/h3#package-index-functions" title="Available H3 Request Helpers"}
-::
-
-You can add more helpers by yourself inside the `~/server/utils` directory.