Small changes to tooltips

[matthew-white]

@issa-tseng writes on Slack:

• instant tooltips are nice but i'd eliminate the fade.
  • it's also a little bottom heavy? like either a px or two needs to be added to the top or taken from the bottom or something between but there's more space at the bottom than the top rn

[matthew-white]

Also:

i'd also knock a px or two off the rounded corner, we don't go too crazy on those in the app