Replace hook_field_widget_form_alter() with hook_field_widget_single_element_form_alter()

This patch solves the issue.

Hi, I have made changes please review and verify.

Hi, your patch does not make something different.

Moreover, it has a typo in comment and in MR you don't change the comment.

I re-attach the original one.

Thank you all for your contribution. The MR will be merged into the dev branch soon.

Automatically closed - issue fixed for 2 weeks with no activity.