remove documentation of non-existent  directory
@@ -53,8 +53,6 @@ Additionally, the following directories may be of interest:
* `/meta`: Documentation relating to the spec's processes that are otherwise untracked (release instructions, etc).
* `/scripts`: Various scripts for generating the spec.
* `/proposals`: Matrix Spec Change (MSC) proposals. See <https://spec.matrix.org/unstable/proposals/>.
-* `/api`: [OpenAPI](https://github.com/OAI/OpenAPI-Specification/blob/master/versions/2.0.md) / Swagger definitions for
- the spec.
## Authoring changes to the spec
