* Add sensor for which stage of heating/cooling is active
for example, a 2-stage heating system would initially use the first stage for heat and if it was unable to fulfill the demand, the thermostat would call for the second stage heat in addition to the first stage heat already in use.
* Add translation keys for english
* Apply suggestions from code review
Co-authored-by: Josef Zweck <24647999+zweckj@users.noreply.github.com>
* Add translation of entity name
* Update sensor name to correctly be translatable
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Co-authored-by: Josef Zweck <24647999+zweckj@users.noreply.github.com>
