feat(node): more headline operations

tests/node.rs

@@ -0,0 +1,24 @@
+use orgize::Org;
+use pretty_assertions::assert_eq;
+
+#[test]
+fn set_content() {
+    let mut org = Org::parse(
+        r#"* title 1
+section 1
+** title 2
+"#,
+    );
+    let headlines: Vec<_> = org.headlines().collect();
+    for headline in headlines {
+        headline.set_title_content(String::from("a *bold* title"), &mut org);
+        headline.set_section_content("and a _underline_ section", &mut org);
+    }
+    let mut writer = Vec::new();
+    org.html(&mut writer).unwrap();
+    assert_eq!(
+        String::from_utf8(writer).unwrap(),
+        "<main><h1>a <b>bold</b> title</h1><section><p>and a <u>underline</u> section</p></section>\
+         <h2>a <b>bold</b> title</h2><section><p>and a <u>underline</u> section</p></section></main>"
+    );
+}