Increase horizontal whitespace between navbar icon links

[gabalafou]

Fixes external issue: Quansight-Labs/czi-scientific-python-mgmt#81

This PR increases the horizontal gap between the navbar icons slightly (1rem to 1.12rem) to align better with accessibility guidelines. The idea is to make sure that the circle targets (pink) do not overlap:

It would be nice if we could rework the navbar icon links to have a known hit area at build time (hit area being the union of width, height, and padding). That way we could calculate the needed horizontal and vertical margins with SCSS, like so:

@mixin enclosing-circle-margin($hit-area-width, $hit-area-height) {
  // the diagonal of the hit area rectangle is also the diameter of the minimum enclosing circle
  $hit-area-diagonal: math.hypot($hit-area-width, $hit-area-height);
  $mx: ($hit-area-diagonal - $hit-area-width) / 2;
  $my: ($hit-area-diagonal - $hit-area-height) / 2;

  margin: $my $mx;
}

But that will have to be for another time.

[Carreau]

error in setup seem unrelated (2to3 install in brew setup fails as it already exists). Not sure why brew try to install Python 3.12... relaunched in case it was fixed upstream

[github-actions]

Coverage report

This PR does not seem to contain any modification to coverable code.

[Carreau]

Ok, test passing.