langchain

9d1867c7 - Update docs to specify Indexing-API-compatible vectorstores (#11581)

Update docs to specify Indexing-API-compatible vectorstores (#11581) **Description:** Update Indexing API docs to specify vectorstores that are compatible with the Indexing API. I add a unit test to remind developers to update the documentation whenever they add or change a vectorstore in a way that affects compatibility. For the unit test I repurposed existing code from [here](https://github.com/langchain-ai/langchain/blob/v0.0.311/libs/langchain/langchain/indexes/_api.py#L245-L257). This is my first PR to an open source project. This is a trivially simple PR whose main purpose is to make me more comfortable submitting Langchain PRs. If this PR goes through I plan to submit PRs with more substantive changes in the near future. **Issue:** Resolves [10482](https://github.com/langchain-ai/langchain/discussions/10482). **Dependencies:** No new dependencies. **Twitter handle:** None.