Improve tap-targets in docs

[summercms]

Just reading the doc's to upgrade from v5 to v6 and can't help but notice the navigation and table of contents links are all squashed up together! This would make navigation on a touch screen a nightmare I'm sure, see screenshot:

Personally I would increase the line-height in the highlighted areas. My finger would clearly cover two links at the same time when trying to press a touch screen.

Can't believe going to link a Lighthouse article to Googler's (lol), see here:

https://web.dev/tap-targets/
GoogleChrome/lighthouse#4358

p.s. Big thanks to the team for the hard work and releasing v6 in record time.