Remove a dangling </summary> tag. (#1509)

Caught while reviewing #1507.

(cherry picked from commit 929894675b32c851ba8625e62c69038bb178387e)

Author: tgrapperon

README.md

@@ -493,7 +493,6 @@ The documentation for releases and `main` are available here:
   * [0.40.2](https://pointfreeco.github.io/swift-composable-architecture/0.40.0/documentation/composablearchitecture/)
   * [0.39.0](https://pointfreeco.github.io/swift-composable-architecture/0.39.0/documentation/composablearchitecture/)
   * [0.38.0](https://pointfreeco.github.io/swift-composable-architecture/0.38.0/documentation/composablearchitecture/)
-  </summary>
 </details>
 
 <br>