Re-add documentation of noise parameter formats.
Re-add 'mgv5_np_ground' noise parameters in group format.
Both these were deleted through auto-generation of conf.example.
Add note to builtin/mainmenu/dlg_settings_advanced.lua that this
documentation must be preserved.
Avoids unreachable code linter warning by moving generation code
(of minetest.conf.example and settings_translation_file.cpp)
out of dlg_settings_advanced.
Due to passing the settings, also it avoids reading the settings file twice.
Instead of activating the code by changing the active if-clauses,
its activation is now done by uncommenting the loadfile() statement.
