Add intermediate stage for text markup.

src/intermediate/italic.rs

@@ -1,5 +1,21 @@
-use super::macros::inoop;
+use super::macros::intermediate;
+use super::IObject;
 
 use crate::error::CustomError;
 
-inoop!(IItalic, Italic);
+#[derive(Debug, Clone)]
+pub(crate) struct IItalic {
+    pub(crate) children: Vec<IObject>,
+}
+
+intermediate!(IItalic, Italic, original, registry, {
+    let children = {
+        let mut ret = Vec::new();
+        for obj in original.children.iter() {
+            ret.push(IObject::new(registry.clone(), obj).await?);
+        }
+        ret
+    };
+
+    Ok(IItalic { children })
+});