fix(curriculum): add/fix an example link in user stories (freeCodeCamp#64153)

Author: pdtrang

curriculum/challenges/english/blocks/lab-multimedia-player/67fccc2463253b213a000142.md

@@ -41,7 +41,7 @@ The `source` element can also be used in the `video` element like this:
 6. Inside the second `section` element, you should have an `h2` element for the title of the video playing.
 7. Below the `h2` element, you should have a `video` element with `controls`, `width` attributes and an `aria-label` attribute.
 8. Inside the `video` element, you should have a `source` element with a `src` attribute pointing to a video file and a `type` attribute. You are free to use this video URL if you like: `https://cdn.freecodecamp.org/curriculum/labs/what-is-the-map-method-and-how-does-it-work.mp4`
-9. Below the `source` element, you should have a `track` element with a `src` attribute pointing to a subtitles file and a `kind` attribute, a `srclang` attribute and a `label` attribute.
+9. Below the `source` element, you should have a `track` element with a `src` attribute pointing to a subtitles file and a `kind` attribute, a `srclang` attribute and a `label` attribute. You are free to use this subtitles URL if you like: `https://cdn.freecodecamp.org/curriculum/labs/what-is-the-map-method-and-how-does-it-work.vtt`
 10. Inside the third `section` element, you should have an `h2` element for the title of the section eg. "Transcript".
 11. Below the `h2` element, you should have a `p` element with the transcript of the video.