Use plural consistently

wiki/src/donate.html

@@ -594,8 +594,8 @@ permitted by law.</strong></p>
       <p><strong>MJ1fqVucBt8YpfPiQTuwBtmLJtzhizx6pz</strong></p>
 
       <p>Supporting more cryptocurrencies implies more work for us:
-      learning how it works, installing the software in a secure place,
-      monitoring its value and trading it, etc.</p>
+      learning how they works, installing the software in a secure place,
+      monitoring their value and trading them, etc.</p>
 
       <p>To make a good use of
       our time, we focus on the ones that are the easiest for us to