This is useful for people using screen readers, since the character used
as a separator won't be read aloud.
Since many screen readers also read content generated via CSS
pseudoelements, we aren't using `content: "|";` or similar but using
elements with a very small width instead.
We're continuing to replace links with buttons, for the reasons
explained in commit 5311daadf.
Since we're using the admin action component, we can also simplify the
logic handling the confirmation message.
In order to avoid duplicate IDs when generating buttons to block the
same author more than once in a page, we're including the record dom_id
in the ID of the button to block an author.
