* Padding over \sqrt and Paths for frac-line
This replaces two earlier PRs.
* Restore reaction arrows
* regenerate screenshots
* Set line padding in a constant
* Update with latest master
* Fix lint error
* update screenshots
* Fix frac lline
For frac-line, use an SVG line in an extra tall span.
I still need to think of a way to adust `vertical-separator`.
* Fix spaces in katex.less
* regenerate screenshots
* update HorizontalBraces and StrikeThrough screenshots
* Change frac-line from border to full span
Change `frac-line` and `vertical-separator`. Instead of using span borders, fill entire span using a `box-shadow`.
This change will enable more dependable engagement of the `min-height` CSS.
* Fix indentation
* Fix indent again
* Change box shadow to inline SVG
* Fix lint error
* regenerate screenshots after switching to SVG for fraction bars