Make markdown table at https://github.com/cmu-delphi/delphi-epidata/blob/08de322948ac6d55ad394d7c2fab62cbd257372b/docs/api/covidcast_signals.md?plain=1#L33-L41 match the current state in https://github.com/cmu-delphi/delphi-epidata/blob/dev/src/server/endpoints/covidcast_utils/descriptions.raw.txt, after recent changes to it in #1334 and #1335, and probably older modifications as well.