I’ve come across a number of releases that either are DVD, VHS, or CD that includes DVD. Sometimes they have the little “video” (TV screen) icon next to them, like here: https://musicbrainz.org/release/5f5e24c7-61e5-3ea5-a669-1346f08796a2 (disc 2), whereas there are several that do not have the video icon - i.e., here: https://musicbrainz.org/release/b3c4bca4-54af-4de6-9b54-fd81a7ba1007 (disc 2)
How can I edit these video releases to add the video icons?
I’m afraid the only way to do that right now is to edit each recording individually and tick the video checkbox. Unless there is a user script to do that.
Don’t know about userscripts – my browser (Brave) doesn’t support them yet, so I just do everything manually – but as that is definitely how you’d do it without them. To clarify though, you need to edit each recording. “Work” would make sense in that context in most discussions outside MB, but our work entities don’t care about the audio/visual distinction. Sorry for being overly pedantic!
I’m not sure what works have to do with this?
You said “edit each work” 
Oh d’uh, though I did link to the recording. 
I’ve edited the post so that it makes sense.