added unique_content_field_validation

config/sync/field.field.node.materiau.field_linked_materials.yml

@@ -5,6 +5,14 @@ dependencies:
   config:
     - field.storage.node.field_linked_materials
     - node.type.materiau
+  module:
+    - unique_content_field_validation
+third_party_settings:
+  unique_content_field_validation:
+    unique: false
+    unique_text: ''
+    unique_multivalue: true
+    unique_multivalue_text: '%value appears more than once in %label'
 id: node.materiau.field_linked_materials
 field_name: field_linked_materials
 entity_type: node