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/inline_source_block.rs

@@ -1,19 +1,18 @@
-use crate::error::CustomError;
-
+use super::macros::intermediate;
 use super::registry::Registry;
+use crate::error::CustomError;
 
 #[derive(Debug, Clone)]
 pub(crate) struct IInlineSourceBlock {
     pub(crate) value: String,
 }
 
-impl IInlineSourceBlock {
-    pub(crate) async fn new<'b, 'parse>(
-        registry: &'b mut Registry<'parse>,
-        original: &'b organic::types::InlineSourceBlock<'parse>,
-    ) -> Result<IInlineSourceBlock, CustomError> {
+intermediate!(
+    IInlineSourceBlock,
+    InlineSourceBlock,
+    |registry, original| async {
         Ok(IInlineSourceBlock {
             value: original.value.to_owned(),
         })
     }
-}
+);