Move File and FileFormat to the crate root

The crate root is not super busy yet, so it's more convenient to have
no public sub modules.

src/file.rs

@@ -1,12 +1,8 @@
-//! Types implementing [`Source`], thus representing some source of
-//! configuration values.
-
 use std::{ffi::OsStr, fs, io, path::{Path, PathBuf}};
 
 use crate::{Config, Error, ErrorInner, Partial, Source};
 
 
-
 impl<C: Config> Source<C> for &Path {
     fn load(&self) -> Result<C::Partial, Error> {
         let ext = self.extension().ok_or_else(|| {

src/lib.rs

@@ -2,18 +2,15 @@ use std::{ffi::OsString, fmt, path::PathBuf};
 
 use serde::Deserialize;
 
-
-pub use serde;
-pub use confique_macro::Config;
-
-
-// #[cfg(feature = "doc-example")]
-// pub mod example;
-
 #[doc(hidden)]
 pub mod internal;
 
-pub mod source;
+mod file;
+
+
+pub use serde;
+pub use confique_macro::Config;
+pub use self::file::{File, FileFormat};
 
 
 /// A configuration object that can be deserialized in layers via `serde`.