Replace icon-edit-square with icon-edit

We currently have four types of edit links/buttons:

• icon-edit-square alone, sometimes in blue or gray
• icon-edit alone, in blue
• icon-edit in white inside an info or primary button
• icon-edit-square in white inside an info or primary button

icon-edit-square is only used when renaming elements from the neighbors header or for renaming processes; we can remove it pretty quickly.