test: Add a bunch examples to the MatrixMockServer docs

Author: poljar

Cargo.lock

@@ -144,6 +144,7 @@ serde_urlencoded = "0.7.1"
 similar-asserts = { workspace = true }
 stream_assert = { workspace = true }
 tracing-subscriber = { workspace = true, features = ["env-filter"] }
+tokio-test = "0.4.4"
 
 [target.'cfg(target_arch = "wasm32")'.dev-dependencies]
 wasm-bindgen-test = "0.3.33"