Make clippy _a little_ more annoying (#10570)

* Clippy: +complexity

* Update client/cli/src/arg_enums.rs

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

* Update bin/node/inspect/src/lib.rs

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

* Update primitives/keystore/src/testing.rs

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

* Update frame/elections/src/lib.rs

Co-authored-by: Keith Yeung <kungfukeith11@gmail.com>

* Update primitives/npos-elections/fuzzer/src/reduce.rs

Co-authored-by: Keith Yeung <kungfukeith11@gmail.com>

* Incorporating feedback

* No need for Ok

* Additional

* Needed slice

* Wigy's suggestions on less derefs

* fix count

* reverting changes brought in by option_map_unit_fn

* add --all-targets

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>
Co-authored-by: Keith Yeung <kungfukeith11@gmail.com>

substrate/primitives/runtime/src/generic/digest.rs

@@ -33,19 +33,13 @@ use crate::{
 use sp_core::RuntimeDebug;
 
 /// Generic header digest.
-#[derive(PartialEq, Eq, Clone, Encode, Decode, RuntimeDebug, TypeInfo)]
+#[derive(PartialEq, Eq, Clone, Encode, Decode, RuntimeDebug, TypeInfo, Default)]
 #[cfg_attr(feature = "std", derive(Serialize, Deserialize, parity_util_mem::MallocSizeOf))]
 pub struct Digest {
 	/// A list of logs in the digest.
 	pub logs: Vec<DigestItem>,
 }
 
-impl Default for Digest {
-	fn default() -> Self {
-		Self { logs: Vec::new() }
-	}
-}
-
 impl Digest {
 	/// Get reference to all digest items.
 	pub fn logs(&self) -> &[DigestItem] {

substrate/primitives/runtime/src/generic/unchecked_extrinsic.rs

@@ -395,7 +395,7 @@ mod tests {
 			info: &DispatchInfoOf<Self::Call>,
 			len: usize,
 		) -> Result<Self::Pre, TransactionValidityError> {
-			Ok(self.validate(who, call, info, len).map(|_| ())?)
+			self.validate(who, call, info, len).map(|_| ())
 		}
 	}