Update link in apis.mdx (#6812)

<!-- Thank you for contributing to LangChain!

Replace this comment with:
  - Description: a description of the change, 
  - Issue: the issue # it fixes (if applicable),
  - Dependencies: any dependencies required for this change,
- Tag maintainer: for a quicker response, tag the relevant maintainer
(see below),
- Twitter handle: we announce bigger features on Twitter. If your PR
gets announced and you'd like a mention, we'll gladly shout you out!

If you're adding a new integration, please include:
1. a test for the integration, preferably unit tests that do not rely on
network access,
  2. an example notebook showing its use.

Maintainer responsibilities:
  - General / Misc / if you don't know who to tag: @dev2049
  - DataLoaders / VectorStores / Retrievers: @rlancemartin, @eyurtsev
  - Models / Prompts: @hwchase17, @dev2049
  - Memory: @hwchase17
  - Agents / Tools / Toolkits: @vowelparrot
  - Tracing / Callbacks: @agola11
  - Async: @agola11

If no one reviews your PR within a few days, feel free to @-mention the
same people again.

See contribution guidelines for more information on how to write/run
tests, lint, etc:
https://github.com/hwchase17/langchain/blob/master/.github/CONTRIBUTING.md
 -->

docs/extras/use_cases/apis.mdx

@@ -9,7 +9,7 @@ If you are just getting started, and you have relatively simple apis, you should
 Chains are a sequence of predetermined steps, so they are good to get started with as they give you more control and let you 
 understand what is happening better.
 
-- [API Chain](/docs/modules/chains/how_to/api.html)
+- [API Chain](/docs/modules/chains/popular/api.html)
 
 ## Agents