Tagging changes for power transformers

[flacombe]

Dear maintainers,

Recent tagging additions has been made to power transformers tagging and some of them could be relevant for ID presets.

transformer=main is now documented on wiki

It is intended to replace discouraged values :

• transformer=traction
• transformer=auto to be replaced by windings:auto=yes
• transformer=minor_distribution

Some voltage keys should also be discouraged. Is it possible to raise a warning regarding the following please ?

• voltage=* in combination with power=transformer
• voltage-high=*
• voltage-low=*

Furthermore, voltage:primary, voltage:secondary, voltage:tertiary are valid with (already in presets) and should require transformer=* (not in validator) to be used.
https://wiki.openstreetmap.org/wiki/Tag:power%3Dtransformer#Voltage_tagging

transformer=* should only be used on nodes (it doesn't raise a warning on area currently), just like power=transformer (which accurately raises a warning when used on areas).

Let me know if any edit is useful in data items, file or elsewhere regarding those improvements.

Best regards.