docs: Update redis_chat_message_history.ipynb (#16344)

## Problem
Spent several hours trying to figure out how to pass
`RedisChatMessageHistory` as a `GetSessionHistoryCallable` with a
different REDIS hostname. This example kept connecting to
`redis://localhost:6379`, but I wanted to connect to a server not hosted
locally.

## Cause
Assumption the user knows how to implement `BaseChatMessageHistory` and
`GetSessionHistoryCallable`

## Solution
Update documentation to show how to explicitly set the REDIS hostname
using a lambda function much like the MongoDB and SQLite examples.

docs/docs/integrations/memory/redis_chat_message_history.ipynb

@@ -139,7 +139,9 @@
     "\n",
     "chain_with_history = RunnableWithMessageHistory(\n",
     "    chain,\n",
-    "    RedisChatMessageHistory,\n",
+    "    lambda session_id: RedisChatMessageHistory(\n",
+    "        session_id, url=\"redis://localhost:6379\"\n",
+    "    ),\n",
     "    input_messages_key=\"question\",\n",
     "    history_messages_key=\"history\",\n",
     ")\n",