feat: Working on documentation

Sources/CliDocCore/Nodes/Group.swift

@@ -2,6 +2,23 @@
 ///
 /// This allows you to group content together, which can optionally be
 /// styled.
+///
+/// ### Example:
+///
+/// ```swift
+/// let group = Group {
+///   "My headline."
+///   "\n"
+///   "Some content".color(.green)
+///   "\n"
+///   "Foo Bar".italic()
+/// }
+///
+/// print(group.render())
+/// ```
+///
+/// ![Group example](group.png)
+///
 public struct Group<Content: TextNode>: TextNode {
 
   @usableFromInline