Improve the choice for Japanese fonts on Linux (and possibly macOS)

Back with Tor Browser 5, I was able to install monafont on my computer and it would allow Shift-JIS fonts to render properly. Because Tor Browser now uses its own built-in fonts to make fingerprinting of system fonts harder, and because there are no SJIS fonts, I can't correctly view any of it. SJIS is extremely sensitive to spacing, so an alternative font which renders the characters but does not render the spacing correctly does not work at all.

SJIS is used extensively on Japanese websites.

Look at https://ja.wikipedia.org/wiki/モナー (or https://ja.wikipedia.org/wiki/%E3%83%A2%E3%83%8A%E3%83%BC if the browser isn't displaying Japanese. Many Japanese characters do not display at all) and see if the examples it displays in SJIS are anything like the image which it displays on the right.

I have not tested on Windows, only Linux.