add @riseup.net to Bridge Relay Help

We need to mention @riseup.net on Tor Launcher's Bridge Relay Help screen. In #11139 (moved), Mike said:

I think this is a good idea, but if we're going to change the Tor Launcher strings, we should try to future proof it, especially if stuff like #11140 (moved) is on the table (though I would prefer limiting the yahoo bridge pool instead of completely removing it), or we want to add new providers later.

Here's the two entities I think we should use instead of the current single entity:

<!ENTITY torsettings.bridgeHelp3.emailDesc "Send email to bridges@torproject.org with the line 'get bridges' by itself in the body of the message.&#160; However, to make it harder for an attacker to learn a lot of bridge addresses, you must send this request from one of the following email address providers (listed in order of preference):">
<!ENTITY torsettings.bridgeHelp3.emailList "https://www.riseup.net, https://mail.google.com, or https://mail.yahoo.com">

This will produce:

Send email to bridges@torproject.org with the line 'get bridges' by itself 
in the body of the message. However, to make it harder for an attacker to 
learn a lot of bridge addresses, you must send this request from one of 
the following email address providers (listed in order of preference):
https://mail.riseup.net, https://mail.google.com, or https://mail.yahoo.com

How is that? Can we make the differing expense of crawling these three any more clear with different (yet concise) text?