docs: fix epoch timestamp precision

changes/ce/feat-12785.en.md

@@ -5,6 +5,6 @@ This new config supports the following values:
 
 - `auto`: Automatically determines the timestamp format based on the log formatter being used.
   Utilizes `rfc3339` format for text formatters, and `epoch` format for JSON formatters.
-- `epoch`: Represents timestamps in milliseconds precision Unix epoch format.
+- `epoch`: Represents timestamps in microseconds precision Unix epoch format.
 - `rfc3339`: Uses RFC3339 compliant format for date-time strings. For example: `2024-03-26T11:52:19.777087+00:00`.
 

rel/i18n/emqx_conf_schema.hocon

@@ -767,7 +767,7 @@ common_handler_timestamp_format.label:
 common_handler_timestamp_format.desc: """~
     Pick a timestamp format:
     - `auto`: automatically choose the best format based on log formatter. `epoch` for JSON and `rfc3339` for text.
-    - `epoch`: Unix epoch time in milliseconds.
+    - `epoch`: Unix epoch time in microseconds.
     - `rfc3339`: RFC3339 format."""
 
 rpc_async_batch_size.desc: