Make the display-after option compatible with display on focus/hover

[wheresrhys]

To replicate something like the default title attribute behaviour - don't show immediately, but show if focus/hover lingers (perhaps indicating that the user is confused and thinking)

[notlee]

A small delay on hover/focus could be a good idea, we should raise this with design when we review o-tooltip (right now there are lots of options, not good guidance, and accessibility issues so an overhaul is due!)

A little context for future us. This is about a tooltip on an interactive button to provide supplementary information. As described at: https://inclusive-components.design/tooltips-toggletips#acasefortooltips