contacts: fix typo

rfc/src/contacts.xml

@@ -59,7 +59,7 @@
 
 <ul spacing="compact">
 <li><t><strong>maxAddressBooksPerCard</strong>: <tt>UnsignedInt|null</tt></t>
-<t>The maximum number of AddressBooks (see <xref target="addressbooks" />) that can be can assigned to a single ContactCard object (see <xref target="contactcards" />). This MUST be an integer &gt;= 1, or null for no limit (or rather, the limit is always the number of AddressBooks in the account).</t></li>
+<t>The maximum number of AddressBooks (see <xref target="addressbooks" />) that can be assigned to a single ContactCard object (see <xref target="contactcards" />). This MUST be an integer &gt;= 1, or null for no limit (or rather, the limit is always the number of AddressBooks in the account).</t></li>
 <li><t><strong>mayCreateAddressBook</strong>: <tt>Boolean</tt></t>
 <t>If true, the user may create an AddressBook in this account.</t></li>
 </ul>