fixed typo

redis.conf

@@ -197,7 +197,7 @@ slave-serve-stale-data yes
 # Note: read only slaves are not designed to be exposed to untrusted clients
 # on the internet. It's just a protection layer against misuse of the instance.
 # Still a read only slave exports by default all the administrative commands
-# such as CONFIG, DEBUG, and so forth. To a limited extend you can improve
+# such as CONFIG, DEBUG, and so forth. To a limited extent you can improve
 # security of read only slaves using 'rename-command' to shadow all the
 # administrative / dangerous commands.
 slave-read-only yes