version: cover the copyrights that are not assigned to the FSF

src/nano.c

@@ -940,6 +940,7 @@ void version(void)
     printf(_(" nano, version %s\n"), VERSION);
 #endif
     printf(" (C) 1999..2016 Free Software Foundation, Inc.\n");
+    printf(_(" (C) 2014..%s the contributors to nano\n"), "2016");
     printf(
 	_(" Email: nano@nano-editor.org	Web: http://www.nano-editor.org/"));
     printf(_("\n Compiled options:"));