Update Sources/docc/DocCDocumentation.docc/snippets.md

Co-authored-by: Pat Shaughnessy <[email protected]>

Author: heckj

Sources/docc/DocCDocumentation.docc/snippets.md

@@ -139,4 +139,10 @@ DocC parses contiguous comments within your the code of a snippet as markdown to
 DocC will attempt to reference symbols from within these comments just like any other documentation content.
 You can reference symbols from your API, which DocC converts into hyperlinks to that symbol when displaying the content.
 
+## Topics
+
+### Directives
+
+- ``Snippet``
+
 <!-- Copyright (c) 2025 Apple Inc and the Swift Project authors. All Rights Reserved. -->