Don't require module name in inherents (#6576)

* Start

* Cleanup `construct_runtime!`

* Add tests

* Fix after merge

* Update the docs

substrate/frame/support/test/tests/construct_runtime_ui/params_in_invalid_module.rs

@@ -1,14 +0,0 @@
-use frame_support::construct_runtime;
-
-construct_runtime! {
-	pub enum Runtime where
-		Block = Block,
-		NodeBlock = Block,
-		UncheckedExtrinsic = UncheckedExtrinsic
-	{
-		System: system::{Module},
-		Balance: balances::<Instance1>::{Call(toto), Origin<I>},
-	}
-}
-
-fn main() {}

substrate/frame/support/test/tests/construct_runtime_ui/params_in_invalid_module.stderr

@@ -1,5 +0,0 @@
-error: `Call` is not allowed to have arguments in parens. Only the following modules are allowed to have arguments in parens: `Inherent`.
-  --> $DIR/params_in_invalid_module.rs:10:40
-   |
-10 |         Balance: balances::<Instance1>::{Call(toto), Origin<I>},
-   |                                              ^^^^^^