minor #1158 [Docs] Fix namespace (NicolasGraph)

This PR was merged into the main branch.

Discussion
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[Docs] Fix namespace

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no <!-- please update src/**/CHANGELOG.md files -->
| Docs?         | yes <!-- required for new features -->
| Issues        | - <!-- prefix each issue number with "Fix #", no need to create an issue if none exist, explain below instead -->
| License       | MIT

Updates SimilaritySearch class namespace in rag-implementation.rst to avoid 404.

Commits
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ae59ba1 Updates SimilaritySearch class namespace in rag-implementation.rst

Author: OskarStark

docs/cookbook/rag-implementation.rst

@@ -118,7 +118,7 @@ Create a tool that performs semantic search on your vector store::
     $toolbox = new Toolbox([$similaritySearch]);
     $processor = new AgentProcessor($toolbox);
 
-The :class:`Symfony\\AI\\Agent\\Toolbox\\Tool\\SimilaritySearch` tool:
+The :class:`Symfony\\AI\\Agent\\Bridge\\SimilaritySearch\\SimilaritySearch` tool:
 
 * Converts the user's query into a vector
 * Searches for similar vectors in the store