sxt: added forgotten prototype;

include/sxt/sxtkey.h

@@ -85,6 +85,9 @@ int sxt_key_generate(sxtkey_t *, int , int );
 /* get 8bit ID from key name */
 uint8_t sxt_key_type_fname(const char *);
 
+/* get cstring name from type of the key */
+const char *sxt_key_name(int);
+
 /* return 0 if key isn't public, 1 otherwise */
 int sxt_key_public(const sxtkey_t *);
 /* return 0 if key isn't private, 1 otherwise */