feat: Working on node builder

Sources/CliDoc/Nodes/LabeledContent.swift

@@ -0,0 +1,46 @@
+public struct LabeledContent: NodeRepresentable {
+
+  @usableFromInline
+  let label: any NodeRepresentable
+
+  @usableFromInline
+  let content: any NodeRepresentable
+
+  @usableFromInline
+  let separator: any NodeRepresentable
+
+  @inlinable
+  public init(
+    separator: (any NodeRepresentable)? = nil,
+    @NodeBuilder label: () -> any NodeRepresentable,
+    @NodeBuilder content: () -> any NodeRepresentable
+  ) {
+    self.separator = separator ?? "\n"
+    self.label = label()
+    self.content = content()
+  }
+
+  @inlinable
+  public func render() -> String {
+    Group(separator: separator) {
+      label
+      content
+    }.render()
+  }
+}
+
+public extension LabeledContent {
+
+  @inlinable
+  init(
+    _ label: String,
+    separator: (any NodeRepresentable)? = nil,
+    @NodeBuilder content: () -> any NodeRepresentable
+  ) {
+    self.init(separator: separator) {
+      Text(label)
+    } content: {
+      content()
+    }
+  }
+}