Refactor to NL:hoofd for main signals with speed limit box

Author: hiddewie

maxspeed_signals.mss

@@ -882,11 +882,11 @@
       marker-height: 16;
     }
 
-    /*****************************************/
-    /* NL speed limit light (no main signal) */
-    /*****************************************/
+    /**********************************************/
+    /* NL speed limit light (part of main signal) */
+    /**********************************************/
     ["feature"="NL"]["signal_speed_limit_form"="light"],
-    ["feature"="NL:snelheid"]["signal_speed_limit_form"="light"] {
+    ["feature"="NL:hoofd"]["signal_speed_limit_form"="light"] {
       marker-width: 16;
       marker-height: 16;
       marker-file: url('symbols/nl/speed_limit_light.png');