Improve config

[Vulpesx]

Makes the interaction with the config nicer for users.

Fix error when languages.toml doesn't exist

Remove unnecessary and also wrong language configs.
Helix default configs are good, you don't need to configure anything in most cases,
also, the configs in adn were outdated and just wrong in some cases.

Don't just append config to the file, parses languages.toml and only adds config if it doesn't already exist.
So adn doesn't override users configs.

[Wilovy09]

@Vulpesx please run cargo clippy -- -D warnings and try to fix the ones that appear, I know that some of them don't apply to you but I don't know if you did the fork when the latest version was not yet released.

I will accept it but when those clippy errors are not there.

I didn't know that with just the installation of the LSP some of them were already working by default.
I learned several things with your 2 PRs (the other one was already approved).

[Vulpesx]

I was waiting if you would approve it before I went through the lints

[Wilovy09]

Thanks! Sorry for making you do that, but the IC throws an error when clippy detects something