Request for API Endpoint to Update Specific Products in Algolia Search Index

- Algolia Client Version: 3.0.0
- Language Version: 3.9

### Description
As of now, I have approximately 2500 instances that require periodic updates in my Algolia search index. The updates are triggered whenever any collection of products is modified. These collections can vary in size, which leads to the following challenges:

**Impracticality of Indexing All Products:** It is not practical for me to index all individual products within a collection due to the potentially large number of products. Indexing each product individually would result in an excessive number of API requests, increasing the time and resources required.

**Time-Consuming Indexing Process:** Currently, indexing around 2500 products one by one is a time-consuming process. Each index operation necessitates an API call, and this accumulates to a significant amount of time and effort.

Given these challenges, I am looking for a solution that would allow me to update specific products within the index efficiently. I believe having an API endpoint that supports batch updates for specific products, possibly by providing a list of product IDs or another means of specifying which products to update, would greatly streamline the process.

The API has `update_records` for partially updating objects, but they are only practical to use when certain fields in the query set have changed. So this cannot be used in this context as well.

This functionality would not only save time and resources but also enhance the overall user experience, particularly for scenarios where only a subset of products within a collection needs updating.

I kindly request your support and consideration in implementing such an API endpoint. If this feature or a similar solution is already available or under consideration, please provide me with guidance on how I can make the best use of it.

### Steps To Reproduce
1. Have an index in algolia with 6k products
2. A collection is updated -- changed the collection name
3. 1k products now have different collection names
4. Index 1k products in Algolia => One by-indexing is time-consuming. indexing 1k products one by one is not practical and overkill.

まず、Python クライアントに既存する update_records API と、issue に記載されているインデックス作成の動作を確認します。コレクション駆動の更新で特定の商品 ID をどのように選択してバッチ化するかを定義し、次に 1,000 商品のシナリオで動作を検証して、完成したエンドポイントの契約を文書化します。

索引モデルが issue の本文から書いたものです。