Inconsistent kwarg names `backgroundcolor` (for `Figure`, `Axis`) and `bgcolor` (for `Legend`)

[maxkapur]

The keyword to change the background color of a Legend is bgcolor:

https://makie.juliaplots.org/v0.17.8/api/index.html#Legend

Whereas the keyword to change the background color of a Axis or Figure is backgroundcolor:

https://makie.juliaplots.org/v0.17.8/api/index.html#Axis

It would be nice if these were consistent.