The language reference's Index is a list of the documentation's contents in
order of appearance. This commit renames "Index" to "Contents" as in table of
contents. It also renames the HTML/CSS identifiers from "index" to "toc".
eeae3a8f9dPaul Espinosa committed on 7/8/2020, 7:31:38 PM· committed by Andrew Kelleyparent6fbb5f0