expand information about accepting foreign currencies

closes #873

www/%username/edit/currencies.spt

@@ -46,6 +46,8 @@ title = participant.username
 subhead = _("Currencies")
 
 [---] text/html
+% from "templates/icons.html" import glyphicon
+
 % extends "templates/profile-edit.html"
 
 % block form
@@ -75,9 +77,27 @@ subhead = _("Currencies")
     % endfor
     </table>
 
-    <p>{{ _("Accepting foreign currencies can complicate things for you, but rejecting them can discourage some donors.") }}</p>
+    <p class="text-info">{{ glyphicon('info-sign') }} {{ _(
+        "Accepting foreign currencies can increase your income by convincing "
+        "people in other countries to donate to you, but international payments "
+        "generate extra fees, and fluctuations in exchange rates can lessen the "
+        "stability of your income."
+    ) }}</p>
+
+    <p class="text-warning">{{ glyphicon('info-sign') }} {{ _(
+        "Stripe automatically converts funds into your main currency, but by "
+        "default PayPal holds payments in foreign currencies until you tell it "
+        "what to do. If you have a Business PayPal account you can choose to "
+        "automatically convert all incoming payments in foreign currencies to "
+        "your main currency. This option is currently located in the "
+        "“{link_open}Preferences for receiving payments{link_close}” page.",
+        link_open='<a href="https://www.paypal.com/businessmanage/preferences/payments"'
+                    ' target="_blank" rel="noopener noreferrer">'|safe,
+        link_close='</a>'|safe
+    ) }}</p>
 
-    <button class="save btn btn-success">{{ _("Save") }}</button>
+    <br>
+    <button class="save btn btn-lg btn-success">{{ _("Save") }}</button>
 </form>
 
 % endblock