The fmt library happily accepts std::string without
any conversions.

Fixes multiple copyright messages in the doxygen docu.

ag '\\file' -L --ignore=ThirdParty *Lib |xargs  sed -i 's/\(.*\)\\copyright/\1\\file\n\1\\copyright/'

Just move and rename the namespace.

clang-tidy modernize-use-emplace check.

Clang format run on near-the-header lines.

Happy New Year

This allows for correct documentation of the process_variables.

Automatically with sed
sed -i 's/ogs_file_param_attr{process/ogs_file_param_attr{prj__processes__process/g'
and similar to the ogs_file_param_special and the ogs_file_param
doxygen commands.