Revert "minor #44464 [TwigBridge] Provide a default non-empty label on empty options to validate HTML5 (DocFX)"

This reverts commit 96e7ae70dc60e19d8c8557ade16e8d6613549ab1, reversing
changes made to f6fb96a95d5d5a039041a733903df525cfad70f3.

Author: nicolas-grekas

Resources/views/Form/form_div_layout.html.twig

@@ -61,7 +61,7 @@
     {%- endif -%}
     <select {{ block('widget_attributes') }}{% if multiple %} multiple="multiple"{% endif %}>
         {%- if placeholder is not none -%}
-            <option value=""{% if required and value is empty %} selected="selected"{% endif %}>{{ placeholder != '' ? (translation_domain is same as(false) ? placeholder : placeholder|trans({}, translation_domain)) : '--' }}</option>
+            <option value=""{% if required and value is empty %} selected="selected"{% endif %}>{{ placeholder != '' ? (translation_domain is same as(false) ? placeholder : placeholder|trans({}, translation_domain)) }}</option>
         {%- endif -%}
         {%- if preferred_choices|length > 0 -%}
             {% set options = preferred_choices %}