It is a wire used as a switch, also to explain the limitations of the base monostable circuit and why the signal conditioner is needed.
You can used Pin 2 as a direct input, but you could run into the illegal condition explained in the article. Why not perform the experiment as see how it works?
You are stuck on a schematic that does not work, you are not going to be able to make it work. You have an working example that is published, complete with exact explanations and illustrations.
I am seriously getting the vib you haven't read most of the article, just looked at the pictures. If this is true, and you haven't asked the type of questions to dispute it, I can not teach you. The whole point of the article is when you have performed the experiment as written you will know the 555 monostable mode, all the why's and wherefore's of how it is done, and how the internal circuit of the 555 does what it does to make it work.
I have just looked up your location. Is it you do not read English? If you are having trouble with specific verbage ask, quote it, those question I can answer.
You are trying to modify a really basic circuit without understanding the basics. Reading is fundamental, there is no substitute.