feat: Adds stacks, working on styles

Sources/CliDoc/Nodes/Group.swift

@@ -1,41 +1,16 @@
-public struct Group: TextNode {
+public struct Group<Content: TextNode>: TextNode {
   @usableFromInline
-  var content: [any TextNode]
-
-  @usableFromInline
-  var separator: any TextNode
+  var content: Content
 
   @inlinable
   public init(
-    separator: any TextNode = "\n",
-    content: [any TextNode]
+    @TextBuilder content: () -> Content
   ) {
-    self.content = content
-    self.separator = separator
-  }
-
-  @inlinable
-  public init(
-    separator: any TextNode = "\n",
-    @TextBuilder content: () -> any TextNode
-  ) {
-    // Check if the content is a NodeContainer, typically is when
-    // using the TextBuilder with more than one text node.
-    //
-    // We need to take over the contents, so we can control the separator.
-    let content = content()
-    if let many = content as? NodeContainer {
-      self.content = many.nodes
-    } else {
-      // We didn't get a NodeContainer, so fallback to just storing
-      // the content.
-      self.content = [content]
-    }
-    self.separator = separator
+    self.content = content()
   }
 
   @inlinable
   public var body: some TextNode {
-    content.map { $0.render() }.joined(separator: separator.render())
+    content
   }
 }