Minor grammar fix.

docs/en/guides/sre/keeper/index.md

@@ -43,7 +43,7 @@ ClickHouse Keeper can be used as a standalone replacement for ZooKeeper or as an
  `False` by default.
 - `max_memory_usage_soft_limit` — Soft limit in bytes of keeper max memory usage. Default value is `max_memory_usage_soft_limit_ratio` * `physical_memory_amount`.
 - `max_memory_usage_soft_limit_ratio` — If `max_memory_usage_soft_limit` is not set or set to zero, we use this value to define the default soft limit. The default value is 0.9.
-- `cgroups_memory_observer_wait_time` — If `max_memory_usage_soft_limit` is not set or set to zero, we use this interval to obeserve the amount of physical memory. Once the change of memory amount is observed, we will recalculate the memory soft limit of Keeper by `max_memory_usage_soft_limit_ratio`. The default value is 15 seconds.
+- `cgroups_memory_observer_wait_time`—If `max_memory_usage_soft_limit` is not set or is set to `0`, we use this interval to observe the amount of physical memory. Once the memory amount changes, we will recalculate Keeper's memory soft limit by `max_memory_usage_soft_limit_ratio`. The default value is 15 seconds.
 - `http_control` — Configuration of [HTTP control](#http-control) interface.
 
 Other common parameters are inherited from the ClickHouse server config (`listen_host`, `logger`, and so on).