Update the documentation for Cargo Tool.
Review Request #11776 — Created Aug. 10, 2021 and submitted
This fleshes out the docs, listing the file types that are supported,
adding installation instructions for the tool, and covering all
configuration options (both worker-side and in Review Board). This
should help users get set up for the first time.
Built the docs. Checked for build and spelling errors and bad links.
"Lintian" is a very unusual word for this. "Lint checks" or "linter checks" are much more common.
Found the second "lintian" on here. Screwed up and accidentally had the whole file in my index when landing another change...
Anyway, I've fixed that second "lintian", and any other fixes can be made in a follow-up commit.