feat: Working on node builder

Sources/CliDoc/Modifiers/LabelStyle.swift

@@ -0,0 +1,48 @@
+import Rainbow
+
+public extension NodeRepresentable {
+
+  @inlinable
+  func labelStyle(_ style: any NodeModifier) -> any NodeRepresentable {
+    return modifier(LabelStyleModifier(style))
+  }
+
+  @inlinable
+  func labelStyle(_ color: NamedColor) -> any NodeRepresentable {
+    return modifier(LabelStyleModifier(.color(color)))
+  }
+
+  @inlinable
+  func labelStyle(_ style: Style) -> any NodeRepresentable {
+    return modifier(LabelStyleModifier(.style(style)))
+  }
+
+  @inlinable
+  func labelStyle(_ styles: Style...) -> any NodeRepresentable {
+    return modifier(LabelStyleModifier(.style(styles)))
+  }
+}
+
+@usableFromInline
+struct LabelStyleModifier: NodeModifier {
+
+  @usableFromInline
+  let modifier: any NodeModifier
+
+  @usableFromInline
+  init(_ modifier: any NodeModifier) {
+    self.modifier = modifier
+  }
+
+  @usableFromInline
+  func render(_ node: any NodeRepresentable) -> any NodeRepresentable {
+    if let node = node as? LabeledContent {
+      return LabeledContent(separator: node.separator) {
+        node.label.modifier(modifier)
+      } content: {
+        node.content
+      }
+    }
+    return node
+  }
+}