Rename the 'show' column setting to 'display'

This also changes toggling to no longer require the setting name to be
prefixed, for example 'show-date' becomes 'date-display' which fits
better with how the other column settings work.
Toggling of the column name will toggle the display setting

This automatically expands the 'display' setting when the setting being
toggled equals the column name, similar to how the view setting
automatically resolve the 'display' setting. As a nice side effect the
old `toggle-id` action is now simply `:toggle id`.