Update comment for generateCompletionScript

The comment was outdated, the resource it pointed to as an example
didn't exist anymore so it could create some confusion as to how to use
the generateCompletionScript.

Author: rderik

Sources/TSCUtility/ArgumentParserShellCompletion.swift

@@ -18,8 +18,8 @@ extension ArgumentParser {
     /// Generates part of a completion script for the given shell.
     ///
     /// These aren't complete scripts, as some setup code is required. See
-    /// `Utilities/bash/completions` and `Utilities/zsh/_swift` for example
-    /// usage.
+    /// `Sources/Commands/Completions+bash.swift` and
+    /// `Sources/Commands/Completions+zsh.swift` for example usage.
     public func generateCompletionScript(for shell: Shell, on stream: OutputByteStream) {
         guard let commandName = commandName else { abort() }
         let name = "_\(commandName.replacingOccurrences(of: " ", with: "_"))"