Fix "incorrect" spelling of header 🙄

https://en.wikipedia.org/wiki/HTTP_referer

Author: itskingori

config/log.conf

@@ -8,7 +8,7 @@ log_format main_json escape=json
     '"body_bytes_sent":"$body_bytes_sent",'
     '"host":"$host",'
     '"http_connection":"$http_connection",'
-    '"http_referrer":"$http_referer",'
+    '"http_referer":"$http_referer",'
     '"http_user_agent":"$http_user_agent",'
     '"http_x_forwarded_for":"$http_x_forwarded_for",'
     '"proxy_x_forwarded_port":"$proxy_x_forwarded_port",'