Explicitly declare decl_storage! getters as functions (#3870)

* parse decl_storage getters with fn keyword

* test for get in decl_storage

* update all decl_storage! getters

* bump version

* adjust missed doc line

substrate/srml/sudo/src/lib.rs

@@ -200,6 +200,6 @@ decl_event!(
 decl_storage! {
 	trait Store for Module<T: Trait> as Sudo {
 		/// The `AccountId` of the sudo key.
-		Key get(key) config(): T::AccountId;
+		Key get(fn key) config(): T::AccountId;
 	}
 }