Mentioned ep_warmup_estimate_time unit in ms

Author: rao-shwe

modules/cli/pages/cbstats/cbstats-warmup.adoc

@@ -48,7 +48,7 @@ Look for values: loading keys, loading access log, and done.
 | Integer
 
 | ep_warmup_estimate_time
-| The time taken to discover the estimated number of keys that may be warmed up.
+| The time taken, measured in milliseconds, to discover the estimated number of keys that may be warmed up.
 | Integer.
 
 | ep_warmup_estimated_key_count