[FIX] *: useless parameter 'placeholder' on fields

addons/mail/models/mail_render_mixin.py

@@ -83,7 +83,7 @@ class MailRenderMixin(models.AbstractModel):
 
     # language for rendering
     lang = fields.Char(
-        'Language', placeholder="${object.partner_id.lang}",
+        'Language',
         help="Optional translation language (ISO code) to select when sending out an email. "
              "If not set, the english version will be used. This should usually be a placeholder expression "
              "that provides the appropriate language, e.g. ${object.partner_id.lang}.")

addons/mail/views/mail_template_views.xml

@@ -65,7 +65,7 @@
                             </page>
                             <page string="Advanced Settings" name="advanced_settings">
                                 <group>
-                                    <field name="lang"/>
+                                    <field name="lang" placeholder="${object.partner_id.lang}"/>
                                     <field name="mail_server_id"/>
                                     <field name="auto_delete"/>
                                     <field name="report_template" domain="[('model','=',model)]"/>