The line break is built into the template on the Editing Help:Article template page so that's why you get it when you copy it over. I just assumed that it was there to highlight the fact that you need to change the search term (otherwise it's buried in the middle of the line), but I tried to delete it and it screws up the format of the page (because the line is so long) so maybe that was the method to the madness.

The added bonus is that someone can't just copy the template over and forget to change the search term.

I added this line below the template which might clear things up:
Note: you need to delete the line break between the two lines of the "Recent Mentions" (your search term should be right next to "&filter..." -- not on a second line). For more advanced "Recent Mentions" usage, check out the RSS help page.

Feel free to clean up the explanation if you can make it clearer or conciser.

-Brian