Use tabular numbers in tables

What are you trying to accomplish?

As tables are frequently used for comparing columns of numeric data (and have the ability to be right-aligned) we should make sure that we make it as easy as possibly. Toggling tabular numbers on givens you the ability to scan columns of numbers effectively, assuming the font supports it.

Here’s an example from a recent PR without this CSS:

and with font-variant: tabular-nums:

What approach did you choose and why?

Flipping the switch with CSS is trivial. If the font doesn’t support this functionality then this doesn’t have any effect, but is no worse than the current behaviour.

What should reviewers focus on?

First commit to Primer. Please let me know if I’m doing anything wrong, especially with the changeset which is new to me.

Can these changes ship as is?

[x] Yes, this PR does not depend on additional changes. 🚢

primer / css