fix status code in cgi script

tests/var/gemini/cgi-bin/test.cgi

@@ -1,6 +1,6 @@
 #!/bin/sh
 
-echo "20 cgi_test"
+printf "%s %s: cgi_test\r\n" "20 text/plain"
 
 echo "env vars:"
 echo $GATEWAY_INTERFACE

tests/var/gemini/cgi-bin/who.cgi

@@ -1,6 +1,7 @@
 #!/bin/sh
 
-echo "20 cgi_test"
+printf "%s %s: cgi_test\r\n" "20 text/plain"
+
 u=""
 if [ -n "${QUERY_STRING}" ]; then
 	u="$(printf "%s" "${QUERY_STRING}" | cut -d'=' -f2)" #yeah, it's awful..