Add ignore_active_older_files description to tail

pipeline/inputs/tail.md

@@ -20,6 +20,7 @@ The plugin supports the following configuration parameters:
 | `refresh_interval`    | The interval of refreshing the list of watched files in seconds.                                                                                                                                                                                                                                                                                                                                                                                                   | `60`      |
 | `rotate_wait`         | Specify the number of extra time in seconds to monitor a file once is rotated in case some pending data is flushed.                                                                                                                                                                                                                                                                                                                                                | `5`       |
 | `ignore_older`        | Ignores files older than `ignore_older`. Supports `m`, `h`, `d` (minutes, hours, days) syntax.                                                                                                                                                                                                                                                                                                                                                                     | Read all. |
+| `ignore_active_older_files`| Ignore files that are older than the value set in `ignore_older` even if the file is being ingested.                                                                                                                                                                                                                                                                                                                                                | `false`       |
 | `skip_long_lines`     | When a monitored file reaches its buffer capacity due to a very long line (`buffer_max_size`), the default behavior is to stop monitoring that file. `skip_long_lines` alter that behavior and instruct Fluent Bit to skip long lines and continue processing other lines that fit into the buffer size.                                                                                                                                                           | `off`     |
 | `skip_empty_lines`    | Skips empty lines in the log file from any further processing or output.                                                                                                                                                                                                                                                                                                                                                                                           | `off`     |
 | `db`                  | Specify the database file to keep track of monitored files and offsets. Recommended to be unique per plugin.                                                                                                                                                                                                                                                                                                                                                                                          | _none_    |