Standard: Typo in protocol bit for MISSION_ITEM_INT

Corrected the reference to the replacement for MISSION_ITEM.
ArduPilot side of mavlink#2362

Author: hamishwillee

message_definitions/v1.0/standard.xml

@@ -17,7 +17,7 @@
       <description>Bitmask of (optional) autopilot capabilities (64 bit). If a bit is set, the autopilot supports this capability.</description>
       <entry value="1" name="MAV_PROTOCOL_CAPABILITY_MISSION_FLOAT">
         <description>Autopilot supports the MISSION_ITEM float message type.
-          Note that MISSION_ITEM is deprecated, and autopilots should use MISSION_INT instead.
+          Note that MISSION_ITEM is deprecated, and autopilots should use MISSION_ITEM_INT instead.
         </description>
       </entry>
       <entry value="2" name="MAV_PROTOCOL_CAPABILITY_PARAM_FLOAT">