Add standard attributes to kaya-otel websocket spans

packages/kaya-otel/README.md

@@ -69,9 +69,13 @@ async def home(ctx: HttpContext):
   `http.response.status_code` when the handler sends the response; 5xx
   statuses mark the span as failed. Exceptions escaping the handler are
   recorded on the span and also mark it as failed.
-- Every WebSocket connection gets one span for its whole lifetime. The close
-  code is recorded as `kaya.websocket.close_code`; exceptions and configured
-  error close codes mark the span as failed.
+- Every WebSocket connection gets one span for its whole lifetime, carrying
+  the applicable standard attributes: `url.scheme`, `url.path`, `url.query`,
+  `network.protocol.name` (`websocket`), `network.transport`,
+  `client.address`/`client.port` and `server.address`/`server.port`. The
+  close code is recorded as `kaya.websocket.close_code`; exceptions and
+  configured error close codes mark the span as failed and set `error.type`
+  (the exception class name, or the close code).
 - W3C `traceparent`/`tracestate` headers on incoming requests are honored,
   so traces propagate from upstream services.
 - Metrics: