Simplecons Update

[SylvesterWilmott]

Simplecons have been updated. Let's update the icons in the client to match.

The recent changes affects the following icons:

24px

• published (Removed).
• unpublished (Removed).
• publish (Added).

The publish icon should replace both all instances of the published and unpublished icons.

16px

• published (Removed).
• publish (Added).
• attention (Updated).
• checklist (Updated).
• cross-outline (Updated).
• pinned (Updated).

The publish icon should replace all instances of the published icon.