custom weight function wrapper (#4158)

* custom weight function wrapper

* dox

* Better tests.

* remove u8 encoding

* Update frame/support/src/weights.rs

Co-Authored-By: thiolliere <gui.thiolliere@gmail.com>

* fix pays fee

Co-authored-by: thiolliere <gui.thiolliere@gmail.com>

substrate/frame/staking/src/lib.rs

@@ -1628,7 +1628,6 @@ impl<T: Trait> Module<T> {
 	/// For each element in the iterator the given number of points in u32 is added to the
 	/// validator, thus duplicates are handled.
 	pub fn reward_by_indices(validators_points: impl IntoIterator<Item = (u32, u32)>) {
-		// TODO: This can be optimised once #3302 is implemented.
 		let current_elected_len = <Module<T>>::current_elected().len() as u32;
 
 		CurrentEraPointsEarned::mutate(|rewards| {

substrate/frame/staking/src/slashing.rs

@@ -649,9 +649,6 @@ fn pay_reporters<T: Trait>(
 	T::Slash::on_unbalanced(value_slashed);
 }
 
-// TODO: function for undoing a slash.
-//
-
 #[cfg(test)]
 mod tests {
 	use super::*;