Store the path to the original source file in the blog post object.

src/command/build/runner.rs

@@ -163,7 +163,7 @@ async fn load_pages(config: &Config) -> Result<Vec<IPage>, CustomError> {
             ret.push(
                 IPage::new(
                     intermediate_context,
-                    PageInput::new(relative_to_pages_dir_path, parsed_document),
+                    PageInput::new(relative_to_pages_dir_path, real_path, parsed_document),
                 )
                 .await?,
             );