Improve localization notes

The links we have in Tor Browser's aboutdialog.dtd file should be updated:

• https://www.torproject.org/donate/donate.html.en should be https://donate.torproject.org/
• https://www.torproject.org/getinvolved/volunteer.html.en should maybe be community.tpo
• https://www.torproject.org/docs/trademark-faq.html.en should be maybe support.tpo
• https://www.torproject.org/getinvolved/relays should maybe be community.tpo/relays