Revert "Allow unused imports for traits used in macros"

This reverts commit 42ea2e9.

The commit spuriously concluded that the unused import warnings
were due to trait use in macros, but actually they were all used in
normal code, not in macros. This appears to simply be a clippy bug
where it treats `as _` as indication that an import is unused, even
though such imports are useful for importing traits that do not
need to be referenced by name.

Author: TheBlueMatt

lightning-block-sync/src/lib.rs

@@ -49,8 +49,7 @@ use bitcoin::hash_types::BlockHash;
 use bitcoin::pow::Work;
 
 use lightning::chain;
-#[allow(unused_imports)] // This thinks trait imports are unused if they're use in macros :(
-use lightning::chain::Listen as _;
+use lightning::chain::Listen;
 
 use std::future::Future;
 use std::ops::Deref;

lightning/src/chain/chainmonitor.rs

@@ -33,9 +33,7 @@ use crate::chain::channelmonitor::{
 	WithChannelMonitor,
 };
 use crate::chain::transaction::{OutPoint, TransactionData};
-#[allow(unused_imports)] // This thinks trait imports are unused if they're use in macros :(
-use crate::chain::Filter as _;
-use crate::chain::{ChannelMonitorUpdateStatus, WatchedOutput};
+use crate::chain::{ChannelMonitorUpdateStatus, Filter, WatchedOutput};
 use crate::events::{self, Event, EventHandler, ReplayEvent};
 use crate::ln::channel_state::ChannelDetails;
 use crate::ln::msgs::{self, BaseMessageHandler, Init, MessageSendEvent, SendOnlyMessageHandler};

lightning/src/chain/channelmonitor.rs

@@ -42,8 +42,7 @@ use crate::chain::package::{
 	HolderHTLCOutput, PackageSolvingData, PackageTemplate, RevokedHTLCOutput, RevokedOutput,
 };
 use crate::chain::transaction::{OutPoint, TransactionData};
-#[allow(unused_imports)] // This thinks trait imports are unused if they're use in macros :(
-use crate::chain::Filter as _;
+use crate::chain::Filter;
 use crate::chain::{BestBlock, WatchedOutput};
 use crate::events::bump_transaction::{AnchorDescriptor, BumpTransactionEvent};
 use crate::events::{ClosureReason, Event, EventHandler, ReplayEvent};

lightning/src/ln/channelmanager.rs

@@ -50,9 +50,7 @@ use crate::chain::channelmonitor::{
 	LATENCY_GRACE_PERIOD_BLOCKS, MAX_BLOCKS_FOR_CONF,
 };
 use crate::chain::transaction::{OutPoint, TransactionData};
-#[allow(unused_imports)] // This thinks trait imports are unused if they're use in macros :(
-use crate::chain::Watch as _;
-use crate::chain::{BestBlock, ChannelMonitorUpdateStatus, Confirm};
+use crate::chain::{BestBlock, ChannelMonitorUpdateStatus, Confirm, Watch};
 use crate::events::{
 	self, ClosureReason, Event, EventHandler, EventsProvider, HTLCHandlingFailureType,
 	InboundChannelFunds, PaymentFailureReason, ReplayEvent,