Address various copy-paste errors

Nice catch @adroitwhiz :)

src/views/conference/2020/index/index.jsx

@@ -85,7 +85,7 @@ const ConferenceSplash = () => (
                     </div>
                 </FlexRow>
                 <p className="conf2020-panel-desc">
-                    <FormattedMessage id="conference-2020.registrationFee" />
+                    <FormattedMessage id="conference-2020.conferenceFee" />
                     <br />
                     <FormattedMessage id="conference-2020.registrationOpen" />
                 </p>
@@ -102,7 +102,7 @@ const ConferenceSplash = () => (
                         id="conference-2020.stayDesc1"
                         values={{
                             hyattLink: <a href="https://www.hyatt.com/en-US/group-booking/BOSRC/G-SCRA">Hyatt Regency Cambridge Hotel​</a>,
-                            acLink: <a href="https://www.hyatt.com/en-US/group-booking/BOSRC/G-SCRA">AC Hotel Boston Cambridge​</a>,
+                            acLink: <a href="https://www.marriott.com/event-reservations/reservation-link.mi?id=1582152189255&key=GRP&app=resvlink">AC Hotel Boston Cambridge​</a>,
                             allstonLink: <a href="https://hotelstudioallston.reztrip.com/ext/promoRate?property=1604&mode=b&pm=true&sr=556197&vr=3">Studio Allston Hotel​</a>
                         }}
                     />

src/views/conference/2020/index/l10n.json

@@ -14,7 +14,7 @@
     "conference-2020.desc5": "Together we'll exchange ideas and strategies on how to use Scratch to engage students in learning to think creatively, reason systematically, and work collaboratively—essential skills for everyone in today’s society.",
 
     "conference-2020.registrationTitle": "Registration:",
-    "conference-2020.registrationFee": "Registration Fee: $250",
+    "conference-2020.conferenceFee": "Conference Fee: $250",
     "conference-2020.registrationOpen": "The conference fee includes 7 meals (3 breakfast, 3 lunches, 1 dinner) plus refreshments during the day. Registration opens on March 3.",
     "conference-2020.register": "Register for the conference!",