Financial — CHAR500 — correct name, it's not CHAR-500

It seems NYS doesn't put the hypen between “CHAR” and “500”, even
though we always did on these pages. I'm not changing the names of
the old files in docs/, as it doesn't seem worth it, but I did change
the textual description inside the anchor tags.

Financial — FY 2020 — fix link to CHAR500

The document was already in the docs/ directory, there was just a
typo in this link here.

Financial — FY 2020 — CHAR500 — Add document to transparency page

Also, apparently NYS writes “CHAR500” not “CHAR-500”. 🤷

Filings ⇒ Transparency, necessary rename operation & related first

The Filings page will ultimately be part of the Transparency page,
but for now, just rename it in prep for later changes.