feat: support cohere's web search

relay/adaptor/cohere/constant.go

@@ -5,3 +5,10 @@ var ModelList = []string{
 	"command-light", "command-light-nightly",
 	"command-r", "command-r-plus",
 }
+
+func init() {
+	num := len(ModelList)
+	for i := 0; i < num; i++ {
+		ModelList = append(ModelList, ModelList[i]+"-internet")
+	}
+}