symptom numbers for fb

Author: nmdefries

docs/api/covidcast-signals/fb-survey.md

@@ -126,7 +126,8 @@ our survey, this means a and (b or c).
 
 COVID-like illness or CLI is not a standard indicator. Through our discussions
 with the CDC, we chose to define it as: fever along with cough or shortness of
-breath or difficulty breathing.
+breath or difficulty breathing. From the list of symptoms from Q1 on
+our survey, this means a and (c or d or e).
 
 Symptoms alone are not sufficient to diagnose influenza or coronavirus
 infections, and so these ILI and CLI indicators are *not* expected to be