Run rustfmt on ln/mod.rs/re-enable it on the ln module

In d257b8a we dropped our old
`rustfmt` per-file exclusion logic and replaced it with
`rustfmt_skip` tags in each previously-skipped files. This had the
unintended consequence of fully disabling `rustfmt` across the
`lightning` crate:

`rustfmt` operates recursively across files in any module it is
told to format. Previously, because we were running `rustfmt` on
each non-excluded file, this meant we wanted to exclude `mod.rs`
and `lib.rs` files - not doing so would result in the entire
module/crate being formatted. However, `cargo fmt --check` only
runs `rustfmt` once - on `lib.rs`. Because we added a top-level
`rustfmt_skip` in `lib.rs` this caused `rustfmt` to ignore it and
all modules.

Here we prepare to fix this by formatting
`lightning/src/ln/mod.rs`.

Author: TheBlueMatt

lightning/src/ln/mod.rs

@@ -1,5 +1,3 @@
-#![cfg_attr(rustfmt, rustfmt_skip)]
-
 // This file is Copyright its original authors, visible in version control
 // history.
 //
@@ -15,15 +13,15 @@
 #[macro_use]
 pub mod functional_test_utils;
 
-pub mod onion_payment;
-pub mod channelmanager;
+pub mod chan_utils;
 pub mod channel_keys;
 pub mod channel_state;
+pub mod channelmanager;
+mod features;
 pub mod inbound_payment;
 pub mod msgs;
+pub mod onion_payment;
 pub mod peer_handler;
-pub mod chan_utils;
-mod features;
 pub mod script;
 pub mod types;
 
@@ -59,64 +57,64 @@ pub use onion_utils::process_onion_failure;
 #[cfg(fuzzing)]
 pub use onion_utils::AttributionData;
 
+#[cfg(all(test, async_payments))]
+#[allow(unused_mut)]
+mod async_payments_tests;
 #[cfg(test)]
 #[allow(unused_mut)]
-pub mod bolt11_payment_tests;
+mod async_signer_tests;
 #[cfg(test)]
 #[allow(unused_mut)]
 mod blinded_payment_tests;
-#[cfg(all(test, async_payments))]
+#[cfg(test)]
 #[allow(unused_mut)]
-mod async_payments_tests;
+pub mod bolt11_payment_tests;
+#[cfg(test)]
+#[allow(unused_mut)]
+mod chanmon_update_fail_tests;
+#[cfg(test)]
+#[allow(unused_mut)]
+mod dual_funding_tests;
 #[cfg(any(test, feature = "_externalize_tests"))]
 #[allow(unused_mut)]
 pub mod functional_tests;
 #[cfg(any(test, feature = "_externalize_tests"))]
 #[allow(unused_mut)]
 pub mod htlc_reserve_unit_tests;
-#[cfg(any(test, feature = "_externalize_tests"))]
-#[allow(unused_mut)]
-pub mod update_fee_tests;
-#[cfg(all(test, splicing))]
-#[allow(unused_mut)]
-mod splicing_tests;
 #[cfg(test)]
 #[allow(unused_mut)]
 mod max_payment_path_len_tests;
 #[cfg(test)]
 #[allow(unused_mut)]
-mod payment_tests;
-#[cfg(test)]
-#[allow(unused_mut)]
-mod priv_short_conf_tests;
-#[cfg(test)]
-#[allow(unused_mut)]
-mod chanmon_update_fail_tests;
-#[cfg(test)]
-#[allow(unused_mut)]
-mod reorg_tests;
+mod monitor_tests;
 #[cfg(test)]
 #[allow(unused_mut)]
-mod reload_tests;
+mod offers_tests;
 #[cfg(test)]
 #[allow(unused_mut)]
 mod onion_route_tests;
 #[cfg(test)]
 #[allow(unused_mut)]
-mod monitor_tests;
+mod payment_tests;
 #[cfg(test)]
 #[allow(unused_mut)]
-mod shutdown_tests;
+mod priv_short_conf_tests;
 #[cfg(test)]
 mod quiescence_tests;
 #[cfg(test)]
 #[allow(unused_mut)]
-mod async_signer_tests;
+mod reload_tests;
 #[cfg(test)]
 #[allow(unused_mut)]
-mod offers_tests;
+mod reorg_tests;
 #[cfg(test)]
 #[allow(unused_mut)]
-mod dual_funding_tests;
+mod shutdown_tests;
+#[cfg(all(test, splicing))]
+#[allow(unused_mut)]
+mod splicing_tests;
+#[cfg(any(test, feature = "_externalize_tests"))]
+#[allow(unused_mut)]
+pub mod update_fee_tests;
 
 pub use self::peer_channel_encryptor::LN_MAX_MSG_LEN;