fix: Change url to nextUrl inside delete-query-params-in-middlewa…

…res.md (#33796)

Co-authored-by: JJ Kasper <[email protected]>

errors/deleting-query-params-in-middlewares.md

@@ -28,7 +28,7 @@ import { NextResponse } from 'next/server'
 export default function middleware(request: NextRequest) {
   const nextUrl = request.nextUrl
   nextUrl.pathname = '/dest'
-  return NextResponse.rewrite(url)
+  return NextResponse.rewrite(nextUrl)
 }
 ```