GeometryRef is not pub

[nms-scribe]

I would like to request that gdal::vector either export GeometryRef or mod geometry.

I keep on running into situations where I want to store the value returned by gdal::vector::geometry::Geometry::get_geometry in a struct without cloning. However, I can't because the following causes a compiler error of "module geometry is private".

use gdal::vector::geometry::GeometryRef;

struct GeometryCache<'a> {
   geometry: GeometryRef<'a>,
   result_of_complicated_analysis_for_future_use: f64
}