client-api: Export nothing with neither client nor server feature active

… to work around a build failure in that configuration.
This configuration is useful either way.

crates/ruma-client-api/CHANGELOG.md

@@ -2,6 +2,8 @@
 
 Breaking changes:
 
+* Export nothing from the crate if neither the `client` nor the `server` feature is active
+  * This may partially be reverted in subsequent releases
 * `UnreadNotificationsCount` has moved from `sync::sync_events::v3` to `sync::sync_events`
 * Remove `PartialEq` implementations for a number of types
   * If the lack of such an `impl` causes problems, please open a GitHub issue

crates/ruma-client-api/src/lib.rs

@@ -5,8 +5,9 @@
 //!
 //! [client-api]: https://spec.matrix.org/v1.2/client-server-api/
 
-#![warn(missing_docs)]
+#![cfg(any(feature = "client", feature = "server"))]
 #![cfg_attr(docsrs, feature(doc_auto_cfg))]
+#![warn(missing_docs)]
 
 pub mod account;
 pub mod alias;

crates/ruma-client-api/tests/uiaa.rs

@@ -1,3 +1,5 @@
+#![cfg(any(feature = "client", feature = "server"))]
+
 use assert_matches::assert_matches;
 use assign::assign;
 use ruma_client_api::{