man: Upgrade Doxyfile config files with doxygen 1.9.1

[echoix]

Upgrades the doxygen configuration files to doxygen 1.9.1, the version currently used in the server that publishes the programming8 manual.

From https://www.doxygen.nl/manual/doxygen_usage.html:

If you have a configuration file generated with an older version of Doxygen, you can upgrade it to the current version by running Doxygen with the -u option.

doxygen -u <config_file>

All configuration settings in the original configuration file will be copied to the new configuration file. Any new options will have their default value. Note that comments that you may have added in the original configuration file will be lost.

Here are the messages logged in the console during the conversion:

$ doxygen -u include/Make/Doxyfile_arch_html.in
warning: Tag 'TCL_SUBST' at line 203 of file 'include/Make/Doxyfile_arch_html.in' has become obsolete.
         This tag has been removed.
warning: Tag 'COLS_IN_ALPHA_INDEX' at line 879 of file 'include/Make/Doxyfile_arch_html.in' has become obsolete.
         This tag has been removed.
warning: Tag 'PERL_PATH' at line 1593 of file 'include/Make/Doxyfile_arch_html.in' has become obsolete.
         This tag has been removed.
warning: Tag 'MSCGEN_PATH' at line 1614 of file 'include/Make/Doxyfile_arch_html.in' has become obsolete.
         This tag has been removed.


Configuration file 'include/Make/Doxyfile_arch_html.in' updated.

$ doxygen -u include/Make/Doxyfile_arch_latex.in
warning: Tag 'TCL_SUBST' at line 203 of file 'include/Make/Doxyfile_arch_latex.in' has become obsolete.
         This tag has been removed.
warning: Tag 'COLS_IN_ALPHA_INDEX' at line 879 of file 'include/Make/Doxyfile_arch_latex.in' has become obsolete.
         This tag has been removed.
warning: Tag 'PERL_PATH' at line 1593 of file 'include/Make/Doxyfile_arch_latex.in' has become obsolete.
         This tag has been removed.
warning: Tag 'MSCGEN_PATH' at line 1614 of file 'include/Make/Doxyfile_arch_latex.in' has become obsolete.
         This tag has been removed.


Configuration file 'include/Make/Doxyfile_arch_latex.in' updated.

This is independent of #6092, but has been compared with the output of #6092 and an un-filed PR dependant of #6092 that enables the disabled features. Only the version_8h.html and version_8h_source.html where GRASS_HEADERS_VERSION and GRASS_HEADERS_DATE are defined changed.
No other config values were changed here, so further PRs will be very clear and isolated which config changes are made

[nilason]

Version 1.9.1 was released in 2021 and is supported by most important platforms. This looks good to me.