fix : remove _{ } syntax from benchmark macro (#7822)

* commented use of common

* hack to pass tests

* another hack

* remove all commented code

* fix the easy tests

* temp hack

* follow through comma hack until better solution

* patch macro

* missed one

* update benchmarks

* update docs

* fix docs

* removed too much

* fix changes

Co-authored-by: Shawn Tabrizi <shawntabrizi@gmail.com>

Author: stanly-johnson

src/benchmarking.rs

@@ -25,8 +25,6 @@ use frame_system::RawOrigin;
 use sp_core::H256;
 
 benchmarks! {
-	_ {	}
-
 	check_equivocation_proof {
 		let x in 0 .. 1;