Add string descriptions for all `LocalizedError`s

[stackotter]

Currently, the default error description is used which is basically just the enum case printed out. Having more human readable and less scary looking descriptions would help regular users troubleshoot a bit better.

[stackotter]

Most newer errors I've added have documentation comments explaining what the error is for so those should be especially easy to create human readable descriptions for. It seems like in swift the current best way to add human readable descriptions is with a switch statement in errorDescription;

public var errorDescription: String? {
    switch self {
    case .customError:
        return "A user-friendly description of the error."
    }
}

[japanese-goblinn]

@stackotter Hi! Is this issue still relevant? I'll be happy to help with it

[stackotter]

Yep it definitely is! Feel free to join the Discord server so that you can easily ask me for clarification on what certain errors are for if it's not clear :)

[japanese-goblinn]

@stackotter Ok, I think that you can assign me on this one and I'll ask you questions if I'll have any 😄

[stackotter]

Sounds good, let me know if you need anything 👍