Use macros for creating the intermediate stage.

This is to make it easier to change function signatures by consolidating the places where the signatures exist.

src/intermediate/horizontal_rule.rs

@@ -1,15 +1,5 @@
+use super::macros::inoop;
+use super::registry::Registry;
 use crate::error::CustomError;
 
-use super::registry::Registry;
-
-#[derive(Debug, Clone)]
-pub(crate) struct IHorizontalRule {}
-
-impl IHorizontalRule {
-    pub(crate) async fn new<'b, 'parse>(
-        registry: &'b mut Registry<'parse>,
-        original: &'b organic::types::HorizontalRule<'parse>,
-    ) -> Result<IHorizontalRule, CustomError> {
-        Ok(IHorizontalRule {})
-    }
-}
+inoop!(IHorizontalRule, HorizontalRule);