New icons take one, props empireoflight, see #23333
New icons: make the .icon32 container larger to prevent clipping, see #23333
Posts screen: show when a post is "locked", hide the checkbox, Quick Edit and Trash links, props dh-shredder, see #23312
Clean up rendering of the title column in the posts list table. Simplify branching. Use get_userdata() rather than get_user_by( 'id' ). Change string to '%s is currently editing'. see #23312.