migrate pallet-remarks to v2 bench syntax (#6291)

Part of:
* #6202

---------

Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
Co-authored-by: GitHub Action <action@github.com>
Co-authored-by: Giuseppe Re <giuseppe.re@parity.io>

prdoc/pr_6291.prdoc

+title: migrate pallet-remarks to v2 bench syntax
+doc:
+- audience: Runtime Dev
+  description: |-
+    Part of:
+    * #6202
+crates:
+- name: pallet-remark
+  bump: patch

substrate/frame/remark/src/benchmarking.rs

@@ -21,7 +21,7 @@
 
 use super::*;
 use alloc::vec;
-use frame_benchmarking::v1::{benchmarks, whitelisted_caller};
+use frame_benchmarking::v2::*;
 use frame_system::{EventRecord, Pallet as System, RawOrigin};
 
 #[cfg(test)]
@@ -34,13 +34,24 @@ fn assert_last_event<T: Config>(generic_event: <T as Config>::RuntimeEvent) {
 	assert_eq!(event, &system_event);
 }
 
-benchmarks! {
-	store {
-		let l in 1 .. 1024*1024;
+#[benchmarks]
+mod benchmarks {
+	use super::*;
+
+	#[benchmark]
+	fn store(l: Linear<1, { 1024 * 1024 }>) {
 		let caller: T::AccountId = whitelisted_caller();
-	}: _(RawOrigin::Signed(caller.clone()), vec![0u8; l as usize])
-	verify {
-		assert_last_event::<T>(Event::Stored { sender: caller, content_hash: sp_io::hashing::blake2_256(&vec![0u8; l as usize]).into() }.into());
+
+		#[extrinsic_call]
+		_(RawOrigin::Signed(caller.clone()), vec![0u8; l as usize]);
+
+		assert_last_event::<T>(
+			Event::Stored {
+				sender: caller,
+				content_hash: sp_io::hashing::blake2_256(&vec![0u8; l as usize]).into(),
+			}
+			.into(),
+		);
 	}
 
 	impl_benchmark_test_suite!(Remark, crate::mock::new_test_ext(), crate::mock::Test);