Feature request: `GI.extent(::Extent)` returns that extent

[asinghvi17]

Super convenient when sanitizing input to convert it all to extents.

[rafaqz]

Is this not a request for Extents.jl?

Otherwise you can certainly add that one line ;)

[asinghvi17]

This is specifically for GeoInterface since it currently returns nothing. But yeah, I might add that at some point - just wanted to make sure people are cool with that

[rafaqz]

Yes I would think returning nothing is a bug