fix the displayed lists of supported countries

www/about/global.spt

@@ -41,26 +41,26 @@ title = _("Global")
 
 <h4>{{ _("Best supported territories") }}</h4>
 
-% set SEPA = constants.SEPA
+% set stripe_countries = constants.PAYOUT_COUNTRIES['stripe']
+% set stripe_sepa_countries = stripe_countries.intersection(constants.SEPA)
 <p>{{ ngettext(
     "",
     "Creators in these {n} territories benefit from all of Liberapay's features:",
-    n=len(SEPA),
+    n=len(stripe_sepa_countries),
 ) }}</p>
 
 <ul class="columns-sm-2 columns-md-4">
 % for country_code, localized_country_name in locale.countries.items()
-% if country_code in SEPA
+% if country_code in stripe_sepa_countries
     <li>{{ localized_country_name }}</li>
 % endif
 % endfor
 </ul>
 
 <h4>{{ _("Well supported territories") }}</h4>
 
-% set stripe_countries = constants.PAYOUT_COUNTRIES['stripe']
 % set paypal_only_countries = constants.PAYOUT_COUNTRIES['paypal'] - stripe_countries
-% set stripe_countries_outside_sepa = stripe_countries - SEPA
+% set stripe_countries_outside_sepa = stripe_countries - constants.SEPA
 <p>{{ ngettext(
     "",
     "Liberapay is also available to creators in the {n} territories listed below. "