L2SS-916: Minor fixes wrt antenna_usage_mask

tangostationcontrol/docs/source/broken_hardware.rst

tangostationcontrol/docs/source/devices/antennafield.rst

tangostationcontrol/docs/source/devices/using.rst

tangostationcontrol/docs/source/index.rst

...tationcontrol/tangostationcontrol/devices/antennafield.py

tangostationcontrol/tangostationcontrol/devices/apsct.py

tangostationcontrol/tangostationcontrol/devices/apspu.py

...tationcontrol/tangostationcontrol/devices/lofar_device.py

...stationcontrol/tangostationcontrol/devices/observation.py

tangostationcontrol/tangostationcontrol/devices/recv.py

...ioncontrol/tangostationcontrol/devices/sdp/digitalbeam.py

tangostationcontrol/tangostationcontrol/devices/unb2.py