Label the file-modified in listing grid cards to differentiate it from the date published

[cgoo4]

By adding this CSS my listing page differentiates the date modified from the date published.

.card-file-modified:before { content: "Updated: "; }

Worth including in the base CSS?

Note, I also changed the file-modified label per below to "Updated" so that the sort-ui: then uses the same label. I thought that would also change the meta label in each of the projects, but they still say "MODIFIED". Not sure if that's a bug?

listing:
  fields: [image, date, title, reading-time, description, file-modified]
  field-display-names:
    file-modified: "Updated"