Update external-kafka.mdx

Co-authored-by: Burak Yigit Kaya <[email protected]>

Author: aldy505

develop-docs/self-hosted/experimental/external-kafka.mdx

@@ -59,7 +59,7 @@ x-snuba-defaults: &snuba_defaults
     KAFKA_SASL_PASSWORD: "<password>"
 ```
 
-If you encounter any failing startup, try to use `consumer` instead of `rust-consumer`.
+If you encounter any failures during installation or startup, try to use `consumer` instead of `rust-consumer`.
 
 ## Relay