plugins/none-ls: use rfc42 style

[MattSturgeon]

• plugins/none-ls: switch to mkNeovimPlugin
• plugins/none-ls: switch sources to rfc42 style
• plugins/none-ls: refactor withArgs deprecation

[MattSturgeon]

 error: function 'anonymous lambda' called without required argument 'options'
at /nix/store/s2b5bnzqsqs5qiyin7l72ck9wwq3j01d-source/plugins/none-ls/servers.nix:1:1:
1| {
| ^
2| pkgs,

I'm confused, the 'anonymous lambda' looks to be the servers.nix module. Why would a module be called without the options argument?