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/src_block.rs

@@ -1,22 +1,17 @@
-use crate::error::CustomError;
-
+use super::macros::intermediate;
 use super::registry::Registry;
+use crate::error::CustomError;
 
 #[derive(Debug, Clone)]
 pub(crate) struct ISrcBlock {
     pub(crate) lines: Vec<String>,
 }
 
-impl ISrcBlock {
-    pub(crate) async fn new<'b, 'parse>(
-        registry: &'b mut Registry<'parse>,
-        original: &'b organic::types::SrcBlock<'parse>,
-    ) -> Result<ISrcBlock, CustomError> {
-        let lines = original
-            .contents
-            .split_inclusive('\n')
-            .map(|s| s.to_owned())
-            .collect();
-        Ok(ISrcBlock { lines })
-    }
-}
+intermediate!(ISrcBlock, SrcBlock, |registry, original| async {
+    let lines = original
+        .contents
+        .split_inclusive('\n')
+        .map(|s| s.to_owned())
+        .collect();
+    Ok(ISrcBlock { lines })
+});