MAINT: Minor compiler fixes

[HaoZeke]

There's one in ioparser but this was enough for me to get around:

In file included from dimreduce.hpp:9:
../libs/tbdefs.hpp: In instantiation of 'std::ostream& toolbox::mpiostream::operator<<(T) [with T = std::valarray<double>; std::ostream = std::basic_ostream<char>]':
../libs/minsearch.hpp:758:18:   required from 'void toolbox::sim_annealing(FCLASS&, const std::valarray<double>&, std::valarray<double>&, double&, AnnealingOptions, std::valarray<std::valarray<double> >, RNG) [with FCLASS = NLDRITERChi; RNG = MTRndUniform; AnnealingOptions = _AnnealingOpts]'
../libs/minsearch.hpp:809:39:   required from 'void toolbox::sim_annealing(FCLASS&, const std::valarray<double>&, std::valarray<double>&, double&, AnnealingOptions, std::valarray<std::valarray<double> >) [with FCLASS = NLDRITERChi; AnnealingOptions = _AnnealingOpts]'
libdimred.cpp:1603:30:   required from here
../libs/tbdefs.hpp:413:18: error: no match for 'operator<<' (operand types are 'std::ostream' {aka 'std::basic_ostream<char'} and 'std::valarray<double>')
  413 |         return os<<data;
      |                ~~^~~~~~
In file included from /home/rgoswami/Git/Github/epfl/lab-cosmo/rgShowcase/.pixi/envs/eon/lib/gcc/x86_64-conda-linux-gnu/13.3.0/include/c++/iostream:41,
                 from ../libs/tbdefs.hpp:19:
/home/rgoswami/Git/Github/epfl/lab-cosmo/rgShowcase/.pixi/envs/eon/lib/gcc/x86_64-conda-linux-gnu/13.3.0/include/c++/ostream:110:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(__ostream_type& (*)(__ostream_type&)) [with _CharT = char; _Traits = std::char_traits<char>; __ostream_type = std::basic_ostream<char>]'
  110 |       operator<<(__ostream_type& (*__pf)(__ostream_type&))
      |       ^~~~~~~~
/home/rgoswami/Git/Github/epfl/lab-cosmo/rgShowcase/.pixi/envs/eon/lib/gcc/x86_64-conda-linux-gnu/13.3.0/include/c++/ostream:110:36: note:   no known conversion for argument 1 from 'std::valarray<double>' to 'std::basic_ostream<char>::__ostream_type& (*)(std::basic_ostream<char>::__ostream_type&)' {aka 'std::basic_ostream<char>& (*)(std::basic_ostream<char>&)'}
  110 |       operator<<(__ostream_type& (*__pf)(__ostream_type&))
      |                  ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
/home/rgoswami/Git/Github/epfl/lab-cosmo/rgShowcase/.pixi/envs/eon/lib/gcc/x86_64-conda-linux-gnu/13.3.0/include/c++/ostream:119:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(__ios_type& (*)(__ios_type&)) [with _CharT = char; _Traits = std::char_traits<char>; __ostream_type = std::basic_ostream<char>; __ios_type = std::basic_ios<char>]'
  119 |       operator<<(__ios_type& (*__pf)(__ios_type&))
      |       ^~~~~~~~
/home/rgoswami/Git/Github/epfl/lab-cosmo/rgShowcase/.pixi/envs/eon/lib/gcc/x86_64-conda-linux-gnu/13.3.0/include/c++/ostream:119:32: note:   no known conversion for argument 1 from 'std::valarray<double>' to 'std::basic_ostream<char>::__ios_type& (*)(std::basic_ostream<char>::__ios_type&)' {aka 'std::basic_ios<char>& (*)(std::basic_ios<char>&)'}
  119 |       operator<<(__ios_type& (*__pf)(__ios_type&))
      |                  ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~
/home/rgoswami/Git/Github/epfl/lab-cosmo/rgShowcase/.pixi/envs/eon/lib/gcc/x86_64-conda-linux-gnu/13.3.0/include/c++/ostream:129:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(std::ios_base& (*)(std::ios_base&)) [with _CharT = char; _Traits = std::char_traits<char>; __ostream_type = std::basic_ostream<char>]'
  129 |       operator<<(ios_base& (*__pf) (ios_base&))

The (re)definition also required changes to distinguish between the ioparser variant.