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
+  }
+}

Sources/CliDoc/Nodes/ShellCommand.swift

@@ -0,0 +1,41 @@
+public struct ShellCommand: NodeRepresentable {
+
+  @usableFromInline
+  let symbol: any NodeRepresentable
+
+  @usableFromInline
+  let command: any NodeRepresentable
+
+  @inlinable
+  public init(
+    @NodeBuilder symbol: () -> any NodeRepresentable,
+    @NodeBuilder command: () -> any NodeRepresentable
+  ) {
+    self.symbol = symbol()
+    self.command = command()
+  }
+
+  @inlinable
+  public init(
+    symbol: String = "  $",
+    @NodeBuilder command: () -> any NodeRepresentable
+  ) {
+    self.init { symbol } command: { command() }
+  }
+
+  @inlinable
+  public init(
+    symbol: String = "  $",
+    command: String
+  ) {
+    self.init { symbol } command: { command }
+  }
+
+  @inlinable
+  public func render() -> String {
+    Group(separator: " ") {
+      symbol
+      command
+    }.render()
+  }
+}