update C14a description

Author: nmdefries

docs/symptom-survey/coding.md

@@ -467,6 +467,8 @@ new items were meant to capture reasons for vaccine hesitancy among respondents.
   were revised and expanded for clarity. Please review the changes carefully
   when you use responses from multiple waves of this survey, since they may
   shift which occupations respondents choose.
+* C14a is a revision of item C14, changed from "the past 5 days" to "the past
+  7 days" to be consistent with other items on the COVID Symptom Survey.
 
 #### New Items
 
@@ -479,5 +481,3 @@ new items were meant to capture reasons for vaccine hesitancy among respondents.
 * Item D1b was previously removed in wave 4 and asks respondents that identify
   as not male if they are currently pregnant.
 * Item D11 ask respondents if they smoke cigarettes.
-* Item C14a asks “In the past 7 days, how often did you wear a mask when in
-  public?”, replacing item C14, which asked only about the past 5 days.