Document all fonts that explicitly require hinting.

[JimBobSquarePants]

Certain True Type fonts only display correctly with hinting enabled. We should document a list.
See SixLabors/Fonts#340 (comment)

https://github.com/freetype/freetype/blob/4d8db130ea4342317581bab65fc96365ce806b77/src/truetype/ttobjs.c#L178-L228