Fix warnings when compiling runtime. (#4332)

* Remove warnings when compiling runtime.

* Remove dispatch::Result imports.

* Add missing imports.

* Fix missing vecs. #4333

* Fix oom function.

* Remove superfluous import.

* More warnings.

substrate/frame/support/procedural/src/construct_runtime/parse.rs

@@ -238,7 +238,7 @@ impl ModuleDeclaration {
 
 	fn default_modules(span: Span) -> Vec<ModulePart> {
 		let mut res: Vec<_> = ["Module", "Call", "Storage"]
-			.into_iter()
+			.iter()
 			.map(|name| ModulePart::with_name(name, span))
 			.collect();
 		res.extend(