Add NixOS support and docs

[Fireye04]

fixes #34

This PR adds NixOS specific paths to search for the nvimunity script, as well as additional documentation regarding getting the project working on declarative nix-based systems. (most of it collapsed by default to avoid clogging up the README).

Edits/ suggestions are welcome.

[Saladin1812]

Hey @Fireye04 great PR !. However I have a more comprehensive implementation here with shift detection & also mounting with the directories / line numbers. https://github.com/Saladin1812/dotfiles/blob/main/nix/home/nvimunity.nix feel free to take inspo. Also i integrated creating a desktop shortcut.

[Fireye04]

That's nice! I didn't want to assume anything about the end user system; eg: I'm running kitty and my nvim is currently set up through nixvim. The derivation you linked appears to have some assumptions about the end user system that I wouldn't necessary want to ascribe to anyone, though it certainly is a more complete alternative.

I'm actually only using unity for a class and will be returning to Godot once it's over, so I don't care too much about what happens here though; if you want to go ahead and PR an alternative derivation, by all means. I just felt inclined to share my solution :)

[Fireye04]

That's nice! I didn't want to assume anything about the end user system; eg: I'm running kitty and my nvim is currently set up through nixvim. The derivation you linked appears to have some assumptions about the end user system that I wouldn't necessary want to ascribe to anyone, though it certainly is a more complete alternative.

I'm actually only using unity for a class and will be returning to Godot once it's over, so I don't care too much about what happens here though; if you want to go ahead and PR an alternative derivation, by all means. I just felt inclined to share my solution :)

[Saladin1812]

That's nice! I didn't want to assume anything about the end user system; eg: I'm running kitty and my nvim is currently set up through nixvim. The derivation you linked appears to have some assumptions about the end user system that I wouldn't necessary want to ascribe to anyone, though it certainly is a more complete alternative.

I'm actually only using unity for a class and will be returning to Godot once it's over, so I don't care too much about what happens here though; if you want to go ahead and PR an alternative derivation, by all means. I just felt inclined to share my solution :)

Yep. Mine is simply a script replacement actually (the terminal assumption is only for desktop shortcut)..however what you are doing is using an sh directly which is great ! So on second thought its a really good solution too. Also for godot you can use my own module Saladin1812/dotfiles@3fa6b58 Allows you specifying default version and use the binary directly.