mathjax/MathJax: MathJax v4.1.0

This release adds a number of new or improved features to MathJax, and fixes several issues in version 4.0.0. These are described in detail in the MathJax v4.1.0 release notes, but among the more important are: Changes to make v4.1 more compatible with older browsers (v4.0 used modern CSS and javascript functions that are not available in some older browsers). Support for a dark-mode color scheme. Movable and sizable dialog boxes (both via the mouse and by keyboard arrow keys). Ability to tab to hyperlinks within typeset expressions. More accurate highlighting of some expressions during exploration. Better handling of tactile Braille output devices in Windows. Better handling of speech for tables and tagged expressions. Better voicing of European-style open interval notation. Fixed arrows in mhchem that were swapped accidentally. More reliable data-latex attributes for TeX output. Better positioning of some accents (e.g., the vector arrow) in Safari and other WebKit-based browsers in CHTML output. Several new configuration options, e.g., to make font loading easier. Improvements to the build system to allow MathJax to be built in Windows power shell.