improve content negotiation page

Hello,

with the previous question on the mailing list about changing language
preference in the browser, I read
https://www.debian.org/intro/cn#howtoset page and I think we could
improve the browsers section (Setting the preferred language in a
browser):

- remove old browsers (Netscape 3 and 4, old versions of Firefox).
- rename "Chromium" to "Chrome and Chromium"
- sort browsers alphabetically


What do you think about it?
I can send a patch or report it in the BTS if you want.


Have a nice day
-- 
Stéphane