feat: Moves core functionality into it's own library.

Sources/CliDoc/Nodes/ShellCommand.swift

@@ -1,3 +1,5 @@
+import Rainbow
+
 public struct ShellCommand<Content: TextNode>: TextNode {
 
   @usableFromInline
@@ -30,3 +32,32 @@ public extension ShellCommand where Content == String {
     self.init(symbol: symbol) { content }
   }
 }
+
+public struct ShellCommandConfiguration {
+  let symbol: any TextNode
+  let content: any TextNode
+}
+
+public extension ShellCommand {
+  func style<S: ShellCommandStyle>(_ style: S) -> some TextNode {
+    style.render(content: .init(symbol: symbol, content: content))
+  }
+}
+
+// MARK: - Style
+
+public protocol ShellCommandStyle: NodeModifier where Self.Content == ShellCommandConfiguration {}
+
+public extension ShellCommandStyle where Self == DefaultShellCommandStyle {
+  static var `default`: Self { DefaultShellCommandStyle() }
+}
+
+public struct DefaultShellCommandStyle: ShellCommandStyle {
+
+  public func render(content: ShellCommandConfiguration) -> some TextNode {
+    HStack {
+      content.symbol
+      content.content.textStyle(.italic)
+    }
+  }
+}