Remove accidental extend of in progress Cohere::Reranking module

Author: infinityrobot

lib/ruby_llm/providers/cohere.rb

@@ -15,7 +15,6 @@ module Cohere
       extend Provider
       extend Cohere::Chat
       extend Cohere::Embeddings
-      extend Cohere::Reranking
       extend Cohere::Models
       extend Cohere::Streaming
       extend Cohere::Tools