AntennaTracker: Fix typos

AntennaTracker/AntennaTracker.txt

@@ -162,7 +162,7 @@ Use Mission Planner to calibrate the tracker:
 - click on OK
 - rotate the complete antenna tracker assembly around, in 3 dimensions, making sure to
 rotate the tracker to every possible orientation in the 1 minute you have
-available. DONT just move the yaw and pitch motors around. You will probably have to
+available. DON'T just move the yaw and pitch motors around. You will probably have to
 pick the whole thing up.
 - At the end of the minute, Mission Planner will update AntennaTrackers compass offsets.
 

AntennaTracker/GCS_Mavlink.cpp

@@ -600,7 +600,7 @@ void GCS_MAVLINK::handleMessage(mavlink_message_t* msg)
                     tracker.nav_status.need_altitude_calibration = true;
                 }
                 if (is_equal(packet.param4,1.0f)) {
-                    // Cant trim radio
+                    // Can't trim radio
                 } else if (is_equal(packet.param5,1.0f)) {
                     result = MAV_RESULT_ACCEPTED;
                     // start with gyro calibration

AntennaTracker/servos.cpp

@@ -190,7 +190,7 @@ void Tracker::update_yaw_position_servo(float yaw)
     // the servo limits are reached and the servo has to slew 360 degrees to the 'other side' to keep tracking.
     //
     // This algorithm accounts for the fact that the antenna mount may not be aligned with North
-    // (in fact, any alignment is permissable), and that the alignment may change (possibly rapidly) over time
+    // (in fact, any alignment is permissible), and that the alignment may change (possibly rapidly) over time
     // (as when the antenna is mounted on a moving, turning vehicle)
     // When the servo is being forced beyond its limits, it rapidly slews to the 'other side' then normal tracking takes over.
     //