in_winevtlog: Add descriptions about xml query for filtering events (fluent#1179)

* in_winevtlog: Add a description for Event_Query parameter

Signed-off-by: Hiroshi Hatake <[email protected]>

* in_winevtlog: Add query languages descriptions for event_query parameter

Signed-off-by: Hiroshi Hatake <[email protected]>

* Update pipeline/inputs/windows-event-log-winevtlog.md

Co-authored-by: Pat <[email protected]>
Signed-off-by: Hiroshi Hatake <[email protected]>

* Update the sentence of supported types of queries.

Co-authored-by: Pat <[email protected]>
Signed-off-by: Hiroshi Hatake <[email protected]>

* Clearify the sentence that describes Event_Query parameter.

Co-authored-by: Pat <[email protected]>
Signed-off-by: Hiroshi Hatake <[email protected]>

---------

Signed-off-by: Hiroshi Hatake <[email protected]>
Co-authored-by: Pat <[email protected]>

Author: cosmo0920

pipeline/inputs/windows-event-log-winevtlog.md

@@ -16,6 +16,7 @@ The plugin supports the following configuration parameters:
 | String\_Inserts | Whether to include StringInserts in output records. \(optional\) | True  |
 | Render\_Event\_As\_XML | Whether to render system part of event as XML string or not. \(optional\) | False  |
 | Use\_ANSI | Use ANSI encoding on eventlog messages. If you have issues receiving blank strings with old Windows versions (Server 2012 R2), setting this to True may solve the problem. \(optional\) | False  |
+| Event\_Query | Specify XML query for filtering events. | `*` |
 
 Note that if you do not set _db_, the plugin will tail channels on each startup.
 
@@ -39,6 +40,12 @@ Here is a minimum configuration example.
 
 Note that some Windows Event Log channels \(like `Security`\) requires an admin privilege for reading. In this case, you need to run fluent-bit as an administrator.
 
+#### Query Languages for Event_Query Parameter
+
+The `Event_Query` parameter can be used to specify the XML query for filtering Windows EventLog during collection.
+The supported query types are [XPath](https://developer.mozilla.org/en-US/docs/Web/XPath) and XML Query.
+For further details, please refer to [the MSDN doc](https://learn.microsoft.com/en-us/windows/win32/wes/consuming-events).
+
 ### Command Line
 
 If you want to do a quick test, you can run this plugin from the command line.