Remove all stale on_runtime_upgrade hooks in the runtime (#10650)

* Remove all stale on_runtime_upgrade hooks in the runtime

* add docs

* cleanup

* fix warn

* fix more warnings

* fix offence test

* overwrite the damn UItest

substrate/frame/contracts/src/migration.rs

@@ -25,6 +25,7 @@ use frame_support::{
 };
 use sp_std::{marker::PhantomData, prelude::*};
 
+/// Wrapper for all migrations of this pallet, based on `StorageVersion`.
 pub fn migrate<T: Config>() -> Weight {
 	use frame_support::traits::StorageVersion;