Gets or sets whether the copy buttons of ShowCodeBlockCopyButton only show while
the pointer is over their block, while they have keyboard focus, and while they confirm a copy.
Hidden, a button keeps its place, its Tab stop and its accessible name. Defaults to
false. Switching it restyles the buttons without re-rendering the document; the viewer
has the :copy-on-hover pseudo-class while it is on.
Can be set from a style, e.g. for every viewer of an application.
public bool ShowCodeBlockCopyButtonOnHover { get; set; }