CG_Buffer3D issues

[robe]

I've been testing out the CG_Buffer3D and have a couple of issues.

1. The function should be renamed CG_3DBuffer to be consistent with CG_3DConvexHull, CG_3DArea, et al.

2. The function at least for me crashes if you feed it a segment size lower than 4 (this is on windows)

POSTGIS="3.6.0dev 3.5.0-74-gf0d1ee2d6" [EXTENSION] PGSQL="170" GEOS="3.13.0-CAPI-1.19.0" SFCGAL="SFCGAL 2.0.0, CGAL 6.0.1, BOOST 1.86.0" PROJ="8.2.1 NETWORK_ENABLED=OFF URL_ENDPOINT=https://cdn.proj.org USER_WRITABLE_DIRECTORY=C:\Users\lr\AppData\Local/proj DATABASE_PATH=C:\ming64\projects\proj\rel-proj-8.2.1w64/share/proj/proj.db" (compiled against PROJ 8.2.1) LIBXML="2.12.5" LIBPROTOBUF="1.2.1" WAGYU="0.5.0 (Internal)"

I'll attach a gdb trace after.

3. The docs say the function supports

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This function supports 3d and will not drop the z-index.

This function supports Polyhedral surfaces.

This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).

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But if you try to pass in anything higher than a string - say like a polygon, it gives error:

ERROR: Input geometry must be a Point or LineString

My use case is mostly points and linestrings so it's still very useful, but we should update the docs if we are not going to support higher before 3.6.0 release.