Fix tons of warnings in newest nightly (#2784)

* Fix tons of warnings in newest nightly

* Fix sr-api-macro doc tests

substrate/core/rpc/src/author/error.rs

@@ -34,7 +34,7 @@ pub enum Error {
 	Pool(txpool::error::Error),
 	/// Verification error
 	#[display(fmt="Extrinsic verification error: {}", "_0.description()")]
-	Verification(Box<::std::error::Error + Send>),
+	Verification(Box<dyn std::error::Error + Send>),
 	/// Incorrect extrinsic format.
 	#[display(fmt="Invalid extrinsic format")]
 	BadFormat,

substrate/core/rpc/src/system/mod.rs

@@ -74,7 +74,7 @@ pub trait SystemApi<Hash, Number> {
 /// System API implementation
 pub struct System<B: traits::Block> {
 	info: SystemInfo,
-	sync: Arc<network::SyncProvider<B>>,
+	sync: Arc<dyn network::SyncProvider<B>>,
 	should_have_peers: bool,
 }
 
@@ -82,7 +82,7 @@ impl<B: traits::Block> System<B> {
 	/// Creates new `System` given the `SystemInfo`.
 	pub fn new(
 		info: SystemInfo,
-		sync: Arc<network::SyncProvider<B>>,
+		sync: Arc<dyn network::SyncProvider<B>>,
 		should_have_peers: bool,
 	) -> Self {
 		System {