Add discernible classes and names to stubs

[saxamaphone69]

Following my comment from #108, I attempted a PR.

I'm sure there is a better way to make the HTML than innerHTML, but it's a start.

[TuxedoTako]

I'm sure there is a better way to make the HTML than innerHTML, but it's a start.

subject here is user generated, and nameBlock contains whatever username is used. This is vulnerable to XSS. Even when the user isn't trying to XSS, putting a < in one of those fields will break how it's displayed.

[saxamaphone69]

I guess as well, if stubs should look like
Subject - Anonymous (where .stub-subject needs ::after { content: ' - '; }
or the margin-right: 1ch that's present now, with no ' - ' breaking up the subject/name.

[TuxedoTako]

I'm curious to see what you'll use these classes for.

[saxamaphone69]

Probably nothing, but glad that the option is there. Appreciate it again.