## Summary of Changes
cosmetic improvements of CMake outputs
### set `FOLDER` for sub-directories of CGAL
In VS Code, the CMake project outline is much cleaner if CGAL is
configured with examples and demos:
<img width="416" height="574" alt="Screenshot_20250911_154221"
src="https://github.com/user-attachments/assets/f39f4ea5-317b-4f2d-ba75-e04691674c27"
/>
### set `CMAKE_MESSAGE_INDENT` to indent the outputs in sub-folders
The output messages from sub-directories are indented, now:
```
== Generating build files for examples ==
-- Configuring examples in examples/AABB_tree
-- Configuring examples in examples/Advancing_front_surface_reconstruction
-- Configuring examples in examples/Algebraic_foundations
-- Configuring examples in examples/Algebraic_kernel_d
NOTICE: This project requires the MPFI library and GMP support, and will not be compiled.
-- Configuring examples in examples/Alpha_shapes_2
-- Configuring examples in examples/Alpha_shapes_3
-- Configuring examples in examples/Alpha_wrap_3
-- Configuring examples in examples/Apollonius_graph_2
-- Configuring examples in examples/Arrangement_on_surface_2
-- Boost include dirs: /usr/include
-- Boost libraries:
-- Using gcc version 4 or later. Adding -frounding-math
-- Configuring examples in examples/BGL_LCC
-- Configuring examples in examples/BGL_OpenMesh
-- Configuring examples in examples/BGL_arrangement_2
-- Configuring examples in examples/BGL_graphcut
-- Configuring examples in examples/BGL_polyhedron_3
Sebastien Loriot
7a311ec821