Draft because more could be done soon. I would love your assistance!

Continuation of similar past efforts with the same goal of refreshing the documentation up a notch.

This is particularly prickly due of the sheer size. There's also a constant fear of possibly losing important information, or making use of incorrect technical terms. A lot of the time is spent reading the original documentation and looking at the source code, too. Fortunately, a decent majority of it is written... quite up to date, too.

• Made the wording match how other classes are documented A LOT more closely;
  • Simplified wording which may be seen as awkward to read, kinda like this very sentence;
  • Use the present simple over future tense when applicable (will return -> returns);
  • Turned some long-winded sentences into notes at the end (and viceversa);
  • Turned some multiple paragraphs into lists;
• Link to other methods and parameters more often;
• Add more examples all around;
• Describe ERR_* constants return values;
• Note more methods moved out of the OS class in the transition to Godot 4;
• All SystemDir constants' descriptions have been prefixed with "Refers to":
  • They could be mistaken to be constant strings, otherwise.

close_midi_inputs, get_connected_midi_inputs, open_midi_inputs

• Link the methods between one another.

get_cmdline_user_args

• Rework description entirely.
  • The previous one was a bit unorganized.

get_keycode_string, find_keycode_from_string

• Add considerably more examples.

request_permission, revoke_granted_permissions

• Rework description entirely.
  • The previous one was absolutely not formatted the same as the rest of the documentation.

get_user_data_dir

• Mention ProjectSettings.application/config/use_custom_user_dir directly.

Feedback is very, very welcome, even in the draft state. And especially right now. This class is huge and very technical.

In fact, I would like to propose a few questions that may help with this cause:

• "Web platform" or "Web platforms"? Capitalized "Web" or not?
• Is OS.move_to_trash() really implemented only on Android, Linux, macOS and Windows?
• Do OS.request_permission and OS.request_permission return true when permissions are granted successfully?
• What does OS.set_use_file_access_save_and_swap really do?