added 'remove_empty_nodes' field from bard to the docs (#1757)

Co-authored-by: Duncan McClean <duncan@doublethree.digital>

Author: Oleafeon

content/collections/fieldtypes/bard.md

@@ -90,6 +90,11 @@ options:
     type: boolean
     description: >
       Always show the "Add Set" button. Default: `false`.
+  -
+    name: remove_empty_nodes
+    type: string
+    description: >
+      Choose how to deal with empty nodes. Options: `false`, `true`, `trim`. Default: `false`.
 
 stage: 1
 id: f4bf58d3-cbce-4957-b883-d92fd4791e89