Fix typo

message_definitions/v1.0/common.xml

@@ -1867,7 +1867,7 @@
           </message>
           <message id="64" name="LOCAL_POSITION_NED_COV">
               <description>The filtered local position (e.g. fused computer vision and accelerometers). Coordinate frame is right-handed, Z-axis down (aeronautical frame, NED / north-east-down convention)</description>
-              <field type="uint32_t" name="time_boot_ms">Timestamp (milliseconds since system boot). 0 for system without monotonic timestam</field>
+              <field type="uint32_t" name="time_boot_ms">Timestamp (milliseconds since system boot). 0 for system without monotonic timestamp</field>
               <field type="uint64_t" name="time_utc">Timestamp (microseconds since UNIX epoch) in UTC. 0 for unknown. Commonly filled by the precision time source of a GPS receiver.</field>
               <field type="uint8_t" name="estimator_type" enum="MAV_ESTIMATOR_TYPE">Class id of the estimator this estimate originated from.</field>
               <field type="float" name="x">X Position</field>