Fix Doxygen warnings

[tinko92]

This PR fixes warnings currently produced by doxygen when building the BG doc.

Some warnings were related to deprecated options. This is fixed with doxygen -u -s Doxyfile, which updates it to the newest version. I used Doxygen 1.14 for that, which seems to be used by the Boost release container. Unfortunately this is (imho) needlessly verbose and adds every available option with its default values. Where it added entire sections, I removed those. For the comments that looked manually written (e.g. explaining the role of HTML output for BG within Boost), I put them manually back in since doxygen removes all comments. Our CI uses Doxygen 1.9.8 from Ubuntu 24.04, so I removed the options added by 1.14 that produced warnings in doxygen 1.9.8.

One warning was about a syntax error in Alias for an unused alias. I removed all unused aliases.

Some warnings were related to missing groups (added) and missing parameter documentation (from an earlier PR of mine, also added).

PR is split into two commits because the first one should be neutral (not change the documentation output at all besides timestamps). To allow verifying that in review, I kept it in a separate commit.

Doxygen has an option to produce a non-zero exit code. My original intent was to fix the warnings, then enable that so the CI can warn about future drift. But since our documentation CI job does not necessarily use the same doxygen version as the Boost release image, I decided against it to avoid this causing problems in the future (e.g. Boost release updating to a future Doxygen version, then erroring on some obsolete option). We could consider adding some script to our documentation CI job that looks at the output and errors on warnings to avoid overlooking e.g. undocumented parameters like in my earlier PR.

[Copilot]

🟢 Approval recommended

The changes are documentation/config focused and the remaining findings are minor text/typo issues with straightforward fixes.

Pull request overview

This PR updates Boost.Geometry Doxygen inputs/configuration to eliminate warnings during documentation builds, including fixing missing/incorrect Doxygen annotations and modernizing Doxyfile settings.

Changes:

• Added missing parameter documentation and corrected Doxygen alias usage to silence warnings.
• Converted an inline example to use \snippet and added matching snippet markers in the example source.
• Updated Doxygen configuration files and added missing group definitions used by \ingroup tags.

File summaries

File	Description
include/boost/geometry/util/normalize_spheroidal_coordinates.hpp	Adds missing \param exact documentation to address undocumented-parameter warnings.
include/boost/geometry/io/wkt/write.hpp	Switches example extraction to \snippet for cleaner Doxygen markup.
include/boost/geometry/geometries/polyhedral_surface.hpp	Fixes a Doxygen alias name for initializer-list constructor docs.
doc/index/Doxyfile	Updates Index-doc Doxygen configuration to newer format/options to reduce warnings.
doc/doxy/doxygen_input/sourcecode/doxygen_1.cpp	Adds snippet block markers corresponding to the \snippet reference.
doc/doxy/doxygen_input/groups/groups.hpp	Adds missing \defgroup entries to satisfy \ingroup usage.
doc/doxy/Doxyfile	Updates main BG Doxygen configuration, including alias formatting and newer defaults.

Review details

Suppressed comments (1)

include/boost/geometry/util/normalize_spheroidal_coordinates.hpp:381

• Typo in parameter documentation: "coordindate" should be "coordinate".

\tparam Units The units of the coordindate system in the spheroid
\tparam CoordinateType The type of the coordinates
\param longitude Longitude
\param exact Whether to use exact antimeridian checks; if false, a relaxed tolerance is used
\ingroup utility

• Files reviewed: 7/7 changed files
• Comments generated: 2
• Review effort level: Lite

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[barendgehrels]

👍 looks good to me! Thanks!