Read a TOML file at path and parse it into fiction.Values

This function currently panics if the TOML file contains any infinities or NaNs

Example

import gleam/dynamic/decode
import fiction
import fiction/providers/toml

type Foo {
  Foo(bar: String)
}

fn foo_decoder() {
  use bar <- decode.then(decode.at(["tools", "example", "bar"], decode.string))

  decode.success(Foo(bar:))
}

pub fn main() {
  let assert Ok(foo) =
    fiction.new()
    |> fiction.join(toml.file("./gleam.toml"))
    |> fiction.extract(foo_decoder())

  assert foo.bar == "baz"
}