[#7845] minor tweaks

Author: xabbuh

reference/forms/types/options/translation_domain.rst.inc

@@ -3,7 +3,7 @@ translation_domain
 
 **type**: ``string``, ``null`` or ``false``  **default**: ``null``
 
-This is the translation domain that will be used for any labels or options
-that are rendered for this field. Use null to use the translation domain of
-the parent form or the default domain of translator for root form. Use false
-to disable translation.
+This is the translation domain that will be used for any label or option
+that is rendered for this field. Use ``null`` to reuse the translation domain
+of the parent form (or the default domain of the translator for the root
+form). Use ``false`` to disable translations.