Document untrigger-filter

Resolves PGMDev#135

Signed-off-by: Pear <[email protected]>

docs/modules/mechanics/actions-triggers.mdx

@@ -39,6 +39,7 @@ In the future, some features that are currently used in Kits may be transferred
   | `id` | Unique identifier used to reference this action from other places in the XML. | <span className="badge badge--primary">String</span> |
   | `scope` | Sets the scope target an action should operate against. | `player`, `team`, or `match` |
   | `filter` | A filter that is tested before running actions inside. | [Filter](/docs/modules/mechanics/filters) |
+  | `untrigger-filter` | Filters if an untrigger event (e.g. a trigger filter stops matching) should be passed down to children, similar to [kit lending](/docs/modules/gear/kits#dynamic-kits). | [Filter](/docs/modules/mechanics/filters) | `never` |
   | `expose` | Allows an action to be triggered by `/action`.<br />*Actions must have an ID and support the match scope for expose to work. Moderators require the `GAMEPLAY` permission to use the action command.* | <span className="badge badge--primary">true/false</span> | false |
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