* Run screenshotter using Chrome 83 and Firefox 76
* Update screenshots
* Update NegativeSpace-chrome screenshot
The new screenshot is correct as per #1194.
* Update Units-chrome screenshot
The new screenshot is correct as per #732 and compared to Firefox.
* Update screenshots
* Support Reaction Arrows
This PR is written to supply reaction arrows for a future `mhchem` extension. `mhchem` uses seven reaction arrows. Four of them correspond to extensible arrows already available in KaTeX. This PR creates the other three.
These arrows will also be useful to chemists writing about reactions when `mhchem` is unavailable.
Three new extensible arrows are introduced: `\xrightleftarrows`, `\xrightequilibrium`, and `\xleftequilibrium`.
These names are not `mhchem`’s user-facing function names. In `mhchem`, users would call these arrows with syntax such as: `\ce{A<-->B}`, or `\ce{A<=>>B}`, or `\ce{A<<=>B}`. I’ve provided names that look more like the other extensible arrow names. That’s probably worth some discussion.
* generate screenshots for ReactionArrows
* Increase overlap in arrow shaft
To prevent a small gap when rendering in very large font sizes.
* Adjust upper text vert alignment. Add warning.
* Limit alignment adjustment to \xleftequilibrium
* generate screenshots for reaction arrows
