[Docs] add info about hardcoded translations

docs/cookbook/promotions/custom-catalog-promotion-action.rst

@@ -253,6 +253,14 @@ And define the translation for our new action type:
                 action:
                     fixed_price: 'Fixed price'
 
+Translations
+------------
+
+Translation keys for catalog promotion action are hardcoded to ``sylius.form.catalog_promotion.action.type`` where ``type`` is one of available catalog promotion actions:
+
+- percentage_discount
+- fixed_discount
+
 Prepare an action template for show page of catalog promotion
 -------------------------------------------------------------
 

docs/cookbook/promotions/custom-catalog-promotion-scope.rst

@@ -189,6 +189,15 @@ In our case - we have a template ``by_phrase.html.twig`` which is first before o
 
     This overriding will be suspect of change, so there won't be need for declaring ``default.html.twig`` template anymore.
 
+Translations
+------------
+
+Translation keys for catalog promotion scope are hardcoded to ``sylius.form.catalog_promotion.scope.type`` where ``type`` is one of available catalog promotion scopes:
+
+- for_products
+- for_taxons
+- for_variants
+
 Prepare a scope template for show page of catalog promotion
 -----------------------------------------------------------