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".
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".