feat: Working on node builder

Sources/CliDoc/Nodes/Section.swift

@@ -0,0 +1,30 @@
+public struct Section: NodeRepresentable {
+
+  @usableFromInline
+  let content: any NodeRepresentable
+
+  public init(@NodeBuilder content: () -> any NodeRepresentable) {
+    self.content = content()
+  }
+
+  public func render() -> String {
+    guard let many = content as? _ManyNode else {
+      return content.render() + "\n\n"
+    }
+
+    let node = _ManyNode(many.nodes, separator: "\n\n")
+    return node.render()
+
+//     var output = ""
+//     let lastIndex = many.nodes.count - 1
+//
+//     for (idx, content) in many.nodes.enumerated() {
+//       if idx != lastIndex {
+//         output += content.render() + "\n\n"
+//       } else {
+//         output += content.render() + "\n"
+//       }
+//     }
+//     return output
+  }
+}