docs: clean up performance checklist formatting (#20830)

* docs: fix list formatting in performance checklist

* docs: remove unused link ref

docs/tutorial/performance.md

@@ -54,13 +54,13 @@ at once, consider the [Chrome Tracing] tool.
 Chances are that your app could be a little leaner, faster, and generally less
 resource-hungry if you attempt these steps.
 
-1) [Carelessly including modules](#1-carelessly-including-modules)
-2) [Loading and running code too soon](#2-loading-and-running-code-too-soon)
-3) [Blocking the main process](#3-blocking-the-main-process)
-4) [Blocking the renderer process](#4-blocking-the-renderer-process)
-5) [Unnecessary polyfills](#5-unnecessary-polyfills)
-6) [Unnecessary or blocking network requests](#6-unnecessary-or-blocking-network-requests)
-7) [Bundle your code](#7-bundle-your-code)
+1. [Carelessly including modules](#1-carelessly-including-modules)
+2. [Loading and running code too soon](#2-loading-and-running-code-too-soon)
+3. [Blocking the main process](#3-blocking-the-main-process)
+4. [Blocking the renderer process](#4-blocking-the-renderer-process)
+5. [Unnecessary polyfills](#5-unnecessary-polyfills)
+6. [Unnecessary or blocking network requests](#6-unnecessary-or-blocking-network-requests)
+7. [Bundle your code](#7-bundle-your-code)
 
 ## 1) Carelessly including modules
 
@@ -418,7 +418,6 @@ As of writing this article, the popular choices include [Webpack][webpack],
 [performance-cpu-prof]: ../images/performance-cpu-prof.png
 [performance-heap-prof]: ../images/performance-heap-prof.png
 [chrome-devtools-tutorial]: https://developers.google.com/web/tools/chrome-devtools/evaluate-performance/
-[chrome-tracing-tutorial]:
 [worker-threads]: https://nodejs.org/api/worker_threads.html
 [web-workers]: https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API/Using_web_workers
 [request-idle-callback]: https://developer.mozilla.org/en-US/docs/Web/API/Window/requestIdleCallback