Update mg_set_protocol_coap.md

docs/c-api/coap.h/mg_set_protocol_coap.md

@@ -6,5 +6,5 @@ signature: |
   int mg_set_protocol_coap(struct mg_connection *nc);
 ---
 
-Set CoAP protocol handler - trigger CoAP specific events 
+Sets CoAP protocol handler - triggers CoAP specific events.