Add camera topic remapping example to dev guide.

Author: hmakelin

docs/pages/developer_guide.rst

@@ -318,6 +318,17 @@ the PX4 User Guide.
 .. seealso::
     `PX4-ROS 2 bridge <https://docs.px4.io/master/en/ros/ros2_comm.html>`_ for more information on the PX4-ROS 2 bridge
 
+Remap ROS 2 Topics
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+By default, the :class:`.CameraInfo` and :class:`px4_msgs.Image` messages are expected at ``camera/camera_info`` and
+``camera/image_raw`` topics, respectively. The topics can be remapped:
+
+.. code-block:: bash
+
+    ros2 run gisnav mock_gps_node --mavros --ros-args --log-level info \
+        --params-file src/gisnav/config/typhoon_h480__ksql_airport_ardupilot.yaml \
+         -r camera/camera_info:=camera_info -r camera/image_raw:=image_raw
+
 Testing
 ====================================================
 Unit & ROS 2 integration tests